A helicopter used by the Red Cross for earthquake relief operations in Pakistan was missing with seven crew members on board, an official said Sunday.

The helicopter lost contact with the air control tower after leaving the northwestern city of Peshawar on Saturday, Red Cross quake relief chief Andre Paquet said.

The helicopter had been chartered by Turkmenistan to the International Committee of the Red Cross for relief work in the quake zone for the past three months. The Mi-8 transport craft was returning to Turkmenistan, Paquet said.

The helicopter left Peshawar around noon Saturday and lost contact with the tower half an hour later after crossing the Afghan border, said Paquet, who did not have any more details.

"We are still searching for the helicopter," he said.

Officials in Afghanistan's Interior Ministry and the airport in Kabul said they were unaware of any reports of a crash inside Afghanistan.

The Oct. 8 quake killed 87,000 people and left around 3.5 million people homeless. Dozens of helicopters are involved in the mammoth relief effort.

In October, four people were killed when a U.N. helicopter heading for the quake zone crashed in Azerbaijan. A Pakistan army helicopter also went down in bad weather that month, killing all six on board.