NATO has opened investigations into a stand-off between French and Turkish ships off the coast of Libya with Ankara accused of continuing to breach a United Nations arms embargo.

Secretary-general Jens Stoltenberg said Nato would look into claims that the Turkish navy ignored French calls for an inspection earlier this month.

Paris has consistently accused Ankara of shipping arms to Libya and wanted to check the ship’s consignment as it was behaving suspiciously, turning off its transponder and failing to give its final destination.

French armed forces minister Florence Parly raised the incident during a Nato meeting of defence chiefs on Thursday and said the Turkish forces put on bullet-proof vests and stood behind weapons as the ship approached.

“There cannot be any complacency with regard to such behaviour. This particularly serious incident must be dealt with and our allies share our concerns because eight European allies gave me clear support today in Nato,” she told French parliamentarians after Thursday’s session.

Turkey has denied the incident. Ankara supports the UN-backed Government of National Accord and has supplied thousands of jihadists in the fight against General Khalifa Haftar’s Libyan National Army, allegedly backed by France.