Turkey has blocked two British minehunter ships from transiting through the country's waters en route to Ukraine, since it would violate an international pact concerning wartime passage of the straits.
Britain said in December that it would transfer two Royal Navy minehunter ships to the Ukrainian Navy to help strengthen its sea operations amid the war with Russia.
Nato member Turkey informed allies that as long as the war continues, it would not allow the vessels to use its Bosphorus and Dardanelles straits, the presidency's communications directorate said.
When Russia launched its invasion of Ukraine in 2022, Turkey triggered the 1936 Montreux Convention, effectively blocking passage of military ships for the warring parties.
The pact exempts ships returning to home bases.
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Turkey has enacted Montreux impartially and meticulously to prevent escalation in the Black Sea, the presidency said.
Ankara maintains good ties with both Ukraine and Russia amid the war.
