Türkiye summoned Ukraine’s ambassador on Saturday after two Turkish-operated commercial vessels were damaged in separate drone attacks in the Black Sea near the Russian port of Tuapse, raising fresh concerns in Ankara about the safety of civilian shipping in the region.

Ukrainian Ambassador Naryman Dzhelialov was called to the Turkish Foreign Ministry in Ankara following attacks on the Lider Bordo Mavi and Lider Kocatepe, according to Turkish Foreign Ministry sources.

The diplomatic move came after the Lider Bordo Mavi was struck Aug. 26 while sailing near Tuapse. The vessel was carrying fresh produce and caught fire after being hit by three drones, according to Turkish shipping and regional sources. Five crew members were injured.

The ship, which flies the Cameroon flag and is operated by a Turkish company, had left the Turkish Black Sea port of Samsun around Aug. 25. It was bound for Tuapse after reportedly being unable to call at the Russian port of Novorossiysk.

A second Turkish-operated vessel, the Lider Kocatepe, was sent to the area the following day to assist the damaged ship. It was also targeted by a drone while en route, sustaining material damage before returning to Samsun, Turkish media reported.