Here are the key developments related to Russia's war in Ukraine this Saturday.
1. Russian troops withdraw from Lyman as Ukraine forces enter town
Ukrainian forces entered the eastern Russian stronghold of Lyman on Saturday after encircling thousands of Russian troops, Kyiv has said.
Moscow has confirmed that its forces have left the town it had been using as a front-line supply hub. The state-owned RIA Novosti agency quoted the Russian defence ministry as saying that "due to the threat of encirclement", Russian soldiers had "retreated to more advantageous lines".
The capture of Lyman, a bastion that is critical for Moscow, would be a major setback for Moscow after President Vladimir Putin proclaimed the annexation of the Donetsk region — where Lyman is situated — along with three other regions on Friday.
"We're already in Lyman, but there are battles," Serhii Cherevatyi, spokesperson for Ukraine's eastern forces, said.
Two grinning Ukrainian soldiers taped the yellow-and-blue national flag on to the "Lyman" welcome sign at the town's entrance in Donetsk region's north, a video posted by the president's chief of staff showed.
"October 1. We're unfurling our state flag and establishing it on our land. Lyman will be Ukraine," one of the soldiers said, standing on the bonnet of a military vehicle.
Ukraine's defence ministry said on Twitter that its air assault forces were entering Lyman.
Ramzan Kadyrov, head of Russia's region of Chechnya and a Putin ally, slammed top commanders for their failings on Saturday — and suggested that Moscow should consider using a low-yield nuclear weapon in Ukraine after a major new defeat on the battlefield.
Earlier on Saturday, a Ukrainian military spokesperson said that Ukraine had encircled thousands of Russian troops at Lyman, which Russia has used as a logistics and transport hub for its operations in the north of the Donetsk region.
"Lyman is important because it is the next step towards the liberation of the Ukrainian Donbas. It is an opportunity to go further to Kreminna and Sievierodonetsk, and it is psychologically very important," Cherevatyi said.
Russia's forces at Lyman totalled around 5,000 to 5,500 soldiers, but the number of encircled troops may have fallen because of casualties and some soldiers trying to break out of the encirclement, he added.
A few hours earlier, US military analysts forecast that Ukraine would likely retake the key Russian-occupied town in the country’s east in the next three days.
"Russian forces continued to withdraw from positions around Lyman on September 30 as Ukrainian forces continued to envelop Russian troops in the area," the Institute for the Study of War, a Washington-based think tank, said in its latest assessment of the war.
Ukrainian officials said on Friday that their troops had captured two villages that lie very close to Lyman, in the clearest sign yet the town could fall.
Ukraine also is making “incremental” gains around Kupiansk and the eastern bank of the Oskil River, which became a key front line since the Ukrainian counteroffensive regained control of the Kharkiv region in September.
2. Russians killed 24 in another convoy attack, claims Ukraine
The governor of the Kharkiv region, Oleh Syniehubov, said on Saturday that 24 civilians were killed in an attack earlier this week on a convoy of people trying to flee the Kupiansk district, calling it "сruelty that can't be justified."
He said 13 children and a pregnant woman were among the dead.
"The Russians fired at civilians almost at point-blank range," Syniehubov wrote on messaging app Telegram.
The Security Service of Ukraine, the secret police force known by the acronym SBU, on Saturday released a video said to show the attacked convoy.
At least one truck appeared to have been blown up, with burned corpses in what remained of its truck bed.
Another vehicle at the front of the convoy also had been ablaze. Bodies lay on the side of the road or still inside vehicles, which appeared pockmarked with bullet holes.
Russia's Defense Ministry said its rockets destroyed Ukrainian military targets in the area, but has not commented on accusations that it targeted civilians fleeing.
Russian troops have retreated from much of the Kharkiv region after a successful Ukrainian counteroffensive last month but have continued to shell the area.
3. Turkey rejects Russia's annexation of four Ukrainian regions
Turkey's Foreign Ministry said on Saturday it rejects Russia's annexation of four regions in Ukraine, adding the decision is a "grave violation" of international law.
Turkey, a NATO member, has conducted a diplomatic balancing act since Russia invaded Ukraine on February 24. Ankara opposes Western sanctions on Russia and has close ties with both Moscow and Kyiv, its Black Sea neighbours. It has also criticised Russia's invasion and sent armed drones to Ukraine.
The Turkish ministry said on Saturday it had not recognised Russia's annexation of Crimea in 2014, adding that it rejects Russia's decision to annex the four regions, Donetsk, Luhansk, Kherson and Zaporizhzhia.
"This decision, which constitutes a grave violation of the established principles of international law, cannot be accepted," the ministry said.
"We reiterate our support to the resolution of this war, the severity of which keeps growing, based on a just peace that will be reached through negotiations," it added.
Russian President Vladimir Putin proclaimed the annexation of the regions on Friday, after Russia held what it called referendums in occupied areas of Ukraine. Western governments and Kyiv said the votes breached international law and were coercive and non-representative.
Russia vetoed a United Nations draft resolution condemning the annexation of eastern Ukraine on Friday evening. Both the UK and US have imposed more sanctions on Russia.
4. Energoatom accuses Russia of 'kidnapping' head of Zaporizhzhia nuclear plant
Ukraine’s nuclear power provider has accused Russia of "kidnapping" the head of the Russian-occupied Zaporizhzhia plant.
The head of Energoatom, the state-owned company in charge of the plant, said on Saturday that Ihor Murashov was detained on his way from Europe's largest nuclear plant to the town of Enerhodar around 16.00 local time (1500 CET) on Friday.
"He was taken out of the car, and with his eyes blindfolded he was driven in an unknown direction," Petro Kotin wrote on the Telegram messaging app, adding there was no immediate word on Murashov's fate.
"His detention by (Russia) jeopardises the safety of Ukraine and Europe’s largest nuclear power plant," Kotin added, calling for Murashov's immediate release.
The United Nations nuclear watchdog later said Russia had confirmed the move. The IAEA said it had been informed by Russian authorities that Murashov was being held for questioning. Moscow, however, has not publicly commented.
The Zaporizhzhia plant has been a focal point of Russia's seven-month invasion of Ukraine, as Moscow and Kyiv accuse each other of shelling the facility, risking a nuclear disaster.
Ukrainian technicians continued running it after Russian troops seized the power station. The plant's last reactor was shut down in September amid ongoing shelling near the facility.
Ukrainian President Volodymyr Zelenskyy has called for area around the plant to be demilitarised.
5. Russia 'killing civilians it now claims are its own citizens' — UK
Russian forces were almost certainly responsible for a deadly missile strike on a convoy southeast of Zaporizhzhia on Friday in which at least 25 civilians were reportedly killed, the British defence ministry says in its latest intelligence update.
The missile involved was probably "a Russian long-range air defence missile being used in a ground attack role", the MoD report says. It adds that Russia's stock of such missiles is likely limited and its use in a ground attack role has likely been "driven by overall munitions shortages".
On Vladimir Putin's illegal annexation of four Ukrainian regions announced on Friday, the ministry notes that "Russia is expending strategically valuable military assets in attempts to achieve tactical advantage and in the process is killing civilians it now claims are its own citizens".
Ukraine’s military claimed on Saturday that Russia would need to deploy cadets before they complete their training because of a lack of manpower in the war. Putin ordered a mass mobilisation of Russian army reservists last week to supplement his troops in Ukraine, and thousands of men have fled the country to avoid the call-up.
The Ukrainian military’s general staff said cadets at the Tyumen Military School and at the Ryazan Airborne School would be sent to participate in Russia’s mobilisation. It offered no details on how it gathered the information, though Kyiv has electronically intercepted mobile phone calls from Russian soldiers amid the conflict.
6. Russia's annexations make war end 'almost' impossible — EU's Borrell
Moscow's annexation of four new occupied Ukrainian territories makes it "almost" impossible to end the war in Ukraine, EU diplomatic chief Josep Borrell said on Saturday.
The annexation of the regions of Donetsk, Lugansk, Zaporizhzhia and Kherson, announced on Friday by Russian President Vladimir Putin, makes it "much more difficult, impossible, almost impossible, to end the war," Borrell said on Spanish television channel RTVE.
"Russia is losing" the war, "it has lost it in moral and political terms", but "Ukraine has not yet won", he said a little later at a forum at La Toja in the northeastern Galicia region, where he defended the European sanctions imposed on Moscow and military aid to Kyiv, and called for perseverance in this direction.
"We must do better than this" and "make the world aware of the reasons and consequences of this war", he pleaded, recalling that Brazil and India had refrained from condemning the Russian annexations at the UN Security Council.
According to Josep Borrell, the Europeans have built "a garden" which is "surrounded by jungle".
"If we do not want the jungle to invade the garden... we will have to get involved," he warned, calling on Europe to strengthen its military arsenal. "This is not a whim... it is necessary, indispensable for survival," he said.
7. New gas pipelines open to reduce Europe's dependency on Russia
Gas started flowing to Poland through the new Baltic Pipe pipeline from Norway via Denmark and the Baltic Sea on Saturday morning, Polish gas pipeline operator Gaz-System said.
The pipeline is at the centre of Poland's strategy to diversify its gas supplies away from Russia that began years before Moscow's February invasion of Ukraine triggered a global energy crisis.
A Gaz-System spokeswoman told Reuters that flows started at 06.10 CET and nominations, or requests for sending gas through the pipeline on October 1, totalled 62.4 million kilowatt-hours (kwh).
The pipeline, with an annual capacity of 10 billion cubic meters, was officially inaugurated on Tuesday, a day after leaks were detected in the subsea Nord Stream gas pipelines linking Russia to Europe.
Russia cut gas supplies to Poland in April when it refused to pay in roubles.
Greece and Bulgariastarted commercial operation of a long-delayed gas pipeline on Saturday which will help decrease southeast Europe's dependence on Russian gas and boost energy security.
The 182-km pipeline will provide a relief to Bulgaria, which has been struggling to secure gas supplies at affordable prices since the end of April, when Russia's Gazprom (GAZP.MM) cut off deliveries over Sofia's refusal to pay in roubles.
European Commission President Ursula von der Leyen heralded the new pipeline as a "game changer" at an inauguration ceremony in Sofia.
Denmark and Sweden said on Friday that leaks in the Nord Stream pipelines were caused by "at least two detonations" with "several hundred kilos" of explosives.
EU leaders warned that leaks discovered on the two natural gas pipelines earlier in the week could be "sabotage".
While the pipelines connecting Russia to Germany still contained some natural gas, the EU said the leaks hadn't affected the bloc's gas supply.