SALANG PASS, Afghanistan – Dense fog hindered rescuers who fanned out across mountainous terrain Monday to search for the wreckage of an Afghan passenger plane that vanished with 44 passengers on board.

After receiving tips from local residents who heard a loud bang, Afghan authorities rushed to the Salang Pass, a major route through the Hindu Kush mountains that connects the capital to the north. Late Monday, they said they suspected the plane may have gone down farther south, closer to its destination of Kabul International Airport.

The plane, operated by Pamir Airways, a private Afghan airline, was traveling from northern Afghanistan to the capital. Myar Rasooli, the head of Kabul airport, said air traffic controllers’ last contact with the plane was when it was about 55 miles north of Kabul. He said there was no distress call from the plane.

The British embassy in Kabul confirmed that three British citizens were aboard the plane but did not identify them. One American also was aboard, said a State Department official in Washington who spoke on condition of anonymity.