KABUL, Jan 18 (Reuters) - A series of avalanches have killed at least 10 people in Afghanistan and authorities were still searching for those feared missing, an official said on Sunday.

The avalanches hit the southern part of the Salang Tunnel on Friday, the main highway linking southern Afghanistan with the north of the country and to central Asia, said Mohammad Rajab who is in charge of the highway.

The avalanches swept away at least 12 passenger vehicles as well as several machines used for clearing snow to keep the highway open, Rajab told Reuters by phone from the area.

"In total, so far, we have recovered 10 dead people and rescued some 40, 11 of whom were hurt by the avalanches. Work is going on to rescue those who are feared trapped," he said.

The highway, which is perched in the middle of the Hindu Kush mountains, at an altitude of 4,450 metres (yards) to the north of Kabul, has been reopened for traffic, he said. (Reporting by Sayed Salahuddin, Editing by Valerie Lee)