Iran has deployed military experts in Russian-occupied Crimea to help launch drone attacks on Ukraine, the White House says.
The United States says it has evidence that Iran is supplying "kamikaze" drones to Russia and training its troops how to use them in Crimea.
"We can confirm that Russian military personnel based in Crimea have been piloting Iranian UAVs and using them to conduct kinetic strikes across Ukraine, including in strikes against Kyiv in recent days," said US State Department spokesman Ned Price.
"We assess that Iranian personnel, Iranian military personnel were on the ground in Crimea and assisted Russia in these operations. Russia has received dozens of these UAVs so far and will likely continue to receive additional shipments in the future."
US officials believe that Iran may have deployed military personnel because of Russia's lack of familiarity with the Iranian-made drones.
Declassified US intelligence findings showed that Russians faced technical problems with the drones soon after taking delivery of the weapons back in August
Kherson 'evacuations' and Russia strikes dam
Around 15,000 people have already been moved from Kherson across the Dnipro River since "evacuations" started on Wednesday, according to Russian-appointed officials.
Kyiv, however, says the movement of people from Kherson are "deportations".
In a video posted on the Telegram messaging app on Thursday, deputy head of Russian-appointed Kherson civil-military administration Kirill Stremousov showed a convoy of buses said to show "evacuees" ferrying people out of areas under evacuation.
Kherson was occupied by Russian forces early on in the war and was annexed by Russia last month in a move that was widely condemned by Western leaders and Kyiv.
Elsewhere in Kherson, Ukrainian President Volodymyr Zelenskyy accused Russians of mining a dam in the Kherson region, in his nightly address.
“According to our information, the aggregates and dam of the Kakhovka Hydroelectric Power Plant were mined by Russian terrorists. Now everyone in the world must act powerfully and quickly to prevent another Russian terrorist attack. Blowing up the dam would mean a large-scale disaster,” Zelenskyy says.