A Russian naval intelligence ship sank off Turkey’s Black Sea coast on Thursday after it collided with a Togo-flagged cargo vessel carrying livestock, Turkey’s coastal safety authority said on its website.

The authority said all 78 personnel aboard the Russian ship were rescued after it sent a tugboat and three fast rescue vessels to the area.

The Russian ship Liman and the other vessel, identified by authorities as Youzarsif H, collided in fog and low visibility in the Black Sea. It occurred 18 miles (29 km) from Kilyos village on the Black Sea coast just north of Istanbul, broadcaster NTV said.

Turkish Prime Minister Binali Yildirim made a call to his Russian counterpart, Dmitry Medvedev, expressing his sadness over the collision–sources in the Turkish prime minister’s office were quoted by Reuters news agency as saying.

No information was immediately available about the state of the Youzarsif H, or its crew or cargo. The Togo-flagged livestock carrier was built in 1977 and has a capacity of 2,418 tons, according to Reuters shipping data.

It was not clear whether either vessel was headed to the Bosphorus Strait from the Black Sea.

Passing through Istanbul, the Bosphorus is one of the world’s most important waterways for oil and grains transit. The 17-mile waterway connects the Black Sea to the Mediterranean.

Polish manufactured intelligence vessel, the Liman served with the USSR’s Northern Fleet before joining the BSF in 1974, according to a Russian-based website.

In 1999, the Liman made international headlines when it was deployed to the Mediterranean to monitor Nato operations against Yugoslavia.

Based at Sevastopol in Crimea, the territory annexed from Ukraine by Russia in 2014, it was a regular visitor to the Syrian port of Tartus for decades, the site notes.