A Turkish cargo ship with 10 crew members aboard sank on Wednesday after a collision with a tanker off Istanbul, Turkish authorities said.

A lifeboat and other debris belonging to the Tugberk Imamoglu have been found but there is no sign of the crew, the General Directorate of Maritime Affairs said in a statement.

“There are 10 seafarers on board, including the captain,” Transport Minister Abdulkadir Uraloglu said. “They are all Turkish. We can say that the sinking occurred rapidly in 11 minutes. No one has been found alive.”

Two helicopters and 12 search and rescue vessels are searching the area.

The ship collided with the Turkish-flagged tanker Alsu in the Marmara Sea at 3 a.m., the statement said. An emergency signal was received from the Tugberk Imamoglu and the first rescue craft reached the site 4:10 a.m.

The vessel, which was carrying rolled steel, collided with the Alsu about 20 miles (32 kilometers) south of Silivri, a western suburb of Turkey’s largest city.

“It is assessed that the Tugberk İmamoglu vessel sank because it did not respond to any calls and the mobile phones of the personnel on board went unanswered,” the maritime directorate said.

The 90-meter (295-foot) cargo ship was traveling from Turkey’s Mediterranean post of Iskenderun to Eregli in the Black Sea. The 91-meter (298-foot) Alsu is an oil or chemical tanker sailing from Kocaeli, east of Istanbul, to Aliaga on the Aegean coast, according to the Marine Traffic website.

The rescue operation comes as Turkish naval units are helping search for a passenger ferry that sank off the coast of Cyprus on Sunday. Eight people died when the Filo Jet sank and 20 remain missing.

The Turkish Straits, comprised of the Bosphorus Strait and Dardanelles Strait at either end of the Marmara Sea, are among the busiest shipping lanes in the world, with hundreds of thousands of vessels transiting between the Mediterranean and Black Seas each year.