CAIRO (AP) — Forces of a Libyan commander who rules the eastern half of the country and who was behind a year-long military attempt to capture the capital, Tripoli, have seized a Turkish vessel heading to the western town of Misrata.

The development by Khalifa Hifter’s forces could escalate tensions in the conflict-stricken Libya, since Turkey is the main foreign backer of Hifter’s rivals, the U.N.-backed administration in Tripoli, in western Libya.

The North African country has been split west to east since it descended into chaos following the 2011 uprising that ousted and killed longtime dictator Moammar Gadhafi.

Hifter’s forces stopped the Jamaica-flagged cargo vessel, Mabrouka, on Monday off the eastern port town of Derna, said Ahmed al-Mosmari, the spokesman for Hifter's forces

The vessel’s crew includes nine Turkish sailors, seven from India and one from Azerbaijan, he said. Al-Mosmari said the vessel entered a “no sail” zone and did not respond to calls from the naval forces.

The private security firm Dryad Global said in a statement that the vessel was sailing from Egypt’s Port Said to Libya’s Mediterranean city of Misrata. It said satellite imagery on Tuesday morning showed the vessel was held at Ras al-Hilal port, which is controlled by Hifter’s forces.

Turkey’s Foreign Ministry on Tuesday confirmed the vessel’s seizure, warning about “dire consequences” and calling on Hifter’s forces to allow the ship to resume its planned voyage, according to a statement carried by the state-run Anadolu news agency.

It's the second Turkish-owned vessel seized by Hifter’s forces this year, according to Ambrey Intelligence, a British private maritime intelligence firm. In 2020, Hifter’s forces seized at least six ships.

Hifter’s forces launched an offensive in April 2019 to try and capture Tripoli from the U.N.-supported government. His campaign, however, collapsed in June, when Tripoli-allied militias, with heavy Turkish support, gained the upper hand in the fighting.

In October, the warring sides agreed to a U.N.-brokered cease-fire, a deal that envisioned the departure of foreign forces and mercenaries from Libya within three months.