Two Turkish-flagged commercial vessels collided in the Sea of Marmara off Istanbul’s Silivri district early Wednesday. Authorities lost contact with one ship and its 10-member crew, triggering a sea-and-air search operation.

Two Turkish-flagged commercial vessels collided in the Sea of Marmara off Istanbul’s Silivri district early Wednesday, after which authorities lost contact with one of the ships and its 10 crew members.

The collision occurred at around 3 am local time, approximately 18 nautical miles south of Silivri, according to the Istanbul Governor’s Office.

The vessels involved were the Alsu, travelling from Kocaeli to Aliağa, and the Tugberk Imamoglu, which was sailing from the southern Turkish port of Iskenderun towards Karadeniz Ereğli on the Black Sea coast.

Contact lost with 10 crew members

Following the collision, Turkish authorities deployed vessels from the General Directorate of Coastal Safety and the Coast Guard Marmara and Straits Command, along with a Coast Guard helicopter, to the area.

Initial assessments found no visible damage to the Alsu. However, authorities were unable to establish contact with the Tugberk Imamoglu or its 10 crew members. Search-and-rescue operations were continuing by sea and air.

The status of the missing crew members was not immediately known. Authorities also had not established the cause of the collision.

Two different types of vessels

According to maritime information cited by Reuters, the Tugberk Imamoglu operates as a bulk carrier, while the Alsu is a chemical tanker. The Tugberk Imamoglu is about 90 metres long, while the Alsu is approximately 91 metres. 

The vessels were travelling on routes connecting Turkey's Black Sea, Mediterranean and Aegean ports when the collision occurred.

Search operation underway

Coast Guard and maritime safety teams continued efforts to locate the missing vessel and its crew.

The incident occurred in the Marmara Sea, part of the wider Turkish Straits system linking the Black Sea with the Mediterranean. The waterways around Istanbul are among the world's busiest maritime routes, making safe navigation particularly important for commercial shipping.

Authorities have not yet released information on casualties, possible environmental damage or the circumstances that led to the collision.

The immediate priority remains locating the Tugberk Imamoglu and the 10 crew members aboard the vessel.