Turkey has blocked a German military vessel from inspecting a cargo ship suspected of carrying weapons on its way to Libya.
On Sunday evening, the German frigate Hamburg stopped the Turkish-flagged cargo ship, Roseline A, as part of a European Union mission called Operation Irini.
But the search had to be abandoned after Ankara protested and denied permission for the vessel to be probed.
Turkey's Foreign Ministry denounced the inspection as "unauthorised and forceful" and says all crewmembers of the freighter were forcibly searched.
Deputy Minister Sedat Onel later summoned the Italian ambassador, the German Embassy's Charge d' Affaires as well as the EU's envoy to Turkey to formally protest the incident.
Germany has rejected Turkey's complaints and states that all protocols were followed in the mission, adding that no weapons or illicit materials were found on the ship.
On Tuesday, Defence Minister Annegret Kramp-Karrenbauer rejected Turkey's accusations and said their protest to the boarding of the vessel was unjustified.
"The soldiers behaved correctly and acted absolutely in line with the mandate of the European mission Irini,” Kramp-Karrenbauer said at a press conference.
Operation Irini was launched by the EU on 31 March to monitor and enforce compliance with the United Nations Security Council Resolution which bans arms shipments to Libya.
The mission uses aerial, satellite, and maritime assets in order to help "bring stability in Libya and peace to its population".
Libya has been torn between two warring factions since the fall of Muammar Gaddafi in 2011: the UN-recognised Tripoli unity government (GNA), which is supported by Turkey, and eastern forces led by Marshal Khalifa Haftar.
The rival sides signed a permanent cease-fire on Friday, but scepticism remains over whether the agreement will be enforced.
Why did Turkey block the search?
German personnel from the Irini mission boarded the Roseline A cargo vessel to search for suspected arms at 17:54 (15:54 CET) on Sunday.
The team met the vessel in international waters, approximately 200 kilometres north of the port of Benghazi, according to a press release.
The vessel had departed Yarimca in Turkey on 20 November and was sailing on course for Misrata in Libya.
The captain of the freighter had cooperated and shared detailed information about the ship's load and voyage, according to the Turkish Foreign Ministry.
Ankara says that armed German forces boarded the vessel by helicopter and conducted a search which lasted for several hours.
"All personnel, including the captain, were searched forcibly, all personnel were gathered and detained in one place, and containers were searched by force, with an armed soldier standing at the captain's head," the Foreign Ministry said in a statement.
Footage released by Demiroren News Agency claims to show German soldiers searching the vessel's crew, who are made to stand with their hands on their head in the control room.
Turkey says the inspection was carried out without their consent, nor that of the ship's captain, and violated international law.
"This intervention, which was initiated upon an ambiguous suspicion and continued until midnight, was terminated only upon the persistent objections of our country."
"We regret the detention of our ship, which seems to have not violated the arms embargo, from its route for hours under severe weather conditions, and the fact that the personnel were treated as criminals during the inspection."
"We protest this act of unauthorized and forceful use," the Ministry stated, adding that they reserve the right to seek compensation for potential damage and losses.
On Tuesday, Defense Minister Hulusi Akar renewed criticism of the German frigate's actions, saying the incident went "against international laws and practices".
No arms materials found onboard
Germany has rejected the allegations by Turkey and says that the mission followed all protocols.
According to a spokesperson in Berlin, the military had warned the Turkish authorities of their intention to inspect the ship, and in the absence of any objection, proceeded to board after four hours in line with international maritime practice.
"If there is no objection within a period of four hours, this is considered as tacit consent," a Defence Ministry spokesperson told Euronews.
"The frigate Hamburg acted in accordance with the instructions of the operation command and along the regulations laid down in the mandate for the operation."
The decision to search was taken not by the German military but by the Operation Irini headquarters in Rome, the spokesperson added.
"The situation on board [Roseline A] was cooperative," the Command of the Bundeswehr also stated on Twitter.
Berlin confirmed that the inspection was subsequently cancelled by mission leadership once Ankara vetoed the search, and says the team remained onboard until they could safely return to the frigate.
"After consultation with the ship's command, the boarding team stayed on board until sunrise in order to be able to return safely to Hamburg," the Ministry said.
In a further statement, Operation Irini said the inspection was carried out "in accordance with relevant UN Security Council resolutions" and that the mission permitted searches in international waters.
"We made good faith efforts to seek the consent of the flag State," the EU said.
"Having received no answer from the flag State, the Master of the ship and its crew assumed a cooperative attitude towards the boarding team."
"When the flag State made it clear that it denied the permission to inspect the vessel, Operation IRINI suspended activities".
All sides have agreed that no illicit material or arms were found onboard the Roseline A during the brief inspection.
Turkey had said that the vessel was transporting food, paints, and humanitarian aid materials from Ambarli Port to Misrata.
The 148-metre long cargo ship was cleared to continue on its voyage to Libya and was expected to make port at 21:00 CET on Monday.
Operation Irini also says that all recommended COVID-19 precautions were observed during the inspection.
Turkish claims of a "double-standard"
According to Operation Irini's guidance, military teams can board a ship for inspection "against the will of the crew" where consent has not been given.
Where boarding is opposed, a team of special forces can "force access" and carry out a search operation that focuses on safety and efficiency.
Sunday's incident was the second example of tensions between Turkey and naval forces from a NATO ally country.
In June, NATO launched an investigation after France said one of its frigates was "lit up'' three times by Turkish naval targeting radar when it tried to approach a Turkish civilian ship suspected of involvement in arms trafficking.
Turkey considers that the EU mission is biased and has accused the EU of blocking arms to the Tripoli government while ignoring those supplied to Khalifa Haftar by his allies.
"The neutrality of Operation Irini ... is currently under discussion," said the Turkish Foreign Ministry.
"It is an operation that does not control the arms support to the putschist Haftar and is used arbitrarily to punish the legitimate Libyan government."
"This double-standard and illegal treatment applied to ships transporting from our country to Libya is never acceptable".
The member countries of Operation Irini - including Germany and France - for their part issued a joint statement on Monday threatening sanctions against "all Libyan or international parties" that could jeopardize the fragile peace process underway in the country.
According to the EU, Irini has helped to document embargo violations by Turkey and Russia, two countries also involved in the conflict.
The inspection of the Roseline A was the fifth boarding activity since the mission was launched.
The bloc also sanctioned a Turkish shipowner guilty of embargo violations in September by freezing his assets.
Annegret Kramp-Karrenbauer stressed that "Turkey is still an important partner for us in NATO," but conceded that the country poses a "big challenge" to European efforts due to its domestic policies and agenda.