There was no immediate news on the fate of the 21-man crew of the Cambodian-registered Hera, a coal-ladden freighter which sank at the northern entrance to the Bosphorus Friday morning. Two search-and-rescue vessels were dispatched to the area, officials said.

And one man was reported missing following the sinking of a second freighter, the Mare, registered in the Caribbean island of Saint Vincent, which collided with another ship late Thursday at the southern end of the Dardanelles Strait, officials said.

Ten crew members of the Mare, which had sailed from Romania, were rescued, officials said. The other ship, the Liberia-flagged Solar Europe, did not suffer major damage.

Meanwhile Anatolia news agency reported that two more ships, registered in Russia and North Korea, had run aground near the entrance to the Bosphorus.

Turkish officials have shut down the Bosphorus and Dardenelles Straits because of adverse weather conditions.

Istanbul's Ataturk Airport was also closed down due to the snow storm which blanketed the city, and caused problems in neighbouring Greece.

Officials in Istanbul ordered the city's schools shut down for the day, and told motorists to only venture out with chains on their tyres.

They were fearful of a repetition of the massive congestion caused last month, when heavy snow left thousands of motorists stranded in freezing temperatures around Istanbul.

TERRA.WIRE