SALANG PASS, Afghanistan -- Dense fog hindered rescuers who fanned out across mountainous terrain on Monday to search for the wreckage of an Afghan passenger plane that vanished with 44 passengers on board. There was no immediate word of casualties.
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 night, 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 Kunduz in 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 (85 kilometers) 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, according to a State Department official in Washington who spoke on condition of anonymity pending notification of family. The nationalities of the two other foreigners were not immediately available.
Six crew members were among the 44 aboard, according to Deputy Transportation Minister Raz Mohammad Alami, who traveled to the crash site with the minister of aviation and other top government officials.
Ismail, a 35-year-old snowplow driver who lives in a village near the pass, said he was taking a morning break when he heard the sound of a crash.
"It was as if there was an accident of two vehicles. I didn't know what it was," said Ismail, who goes by one name.
At the request of the Afghan government, NATO dispatched a fixed-wing plane to the last known position of the aircraft. Capt. Robert Leese, a spokesman for the NATO air unit assisting in the search, said the U.S. plane got within four miles (seven kilometers) of the suspected crash site, but had to turn back because of bad weather.
"The fog was so bad you couldn't tell where the mountain began and the fog ended," Leese said.
NATO helicopters were on standby at Bagram Air Field and at the Kabul airport to assist in any rescue effort, NATO said in a statement. The Afghan Defense Ministry also ordered the nation's air force to be on standby. Ambulances also were dispatched to the pass.
When low cloud cover and fog hampered the aerial search, about 70 rescue workers began ascending the mountains on foot to find the wreckage. That foot patrol, which included the governor of Parwan province, descended the mountains about an hour later after authorities began to suspect that the plane had traveled farther south toward Kabul before going down.
Alami said authorities now believe the plane crashed about 12 miles (20 kilometers) north of the capital, possibly in the Ghorband district of Parwan province. He said the governor had asked officials in the province's dozen districts to help locate the wreckage.
Jaweed Stanikzai, the brother of a passenger on the plane, told The Associated Press at the Kabul airport that he last talked to his brother at 8 a.m.
"He told us that he was on the plane and could not talk, but would call us as soon as he could," he said. "Nobody is providing us any information about the incident."
Kabul-based Pamir Airways started operations in 1995. It has daily flights to major Afghan cities and also operates flights to Dubai and Saudi Arabia for the hajj pilgrimage.
According to its website, Pamir uses Antonov An-24 type aircraft on all its Kunduz-to-Kabul flights.
Pamir's chief executive officer, Amanullah Hamid, said the plane was last inspected about three months ago in Bulgaria.
The An-24 is a medium-range twin-turboprop civil aircraft built in the former Soviet Union from 1950 to 1978. Although production there ceased more than three decades ago, a modernized version is still being made in China.
It is widely used by airlines in the developing world due to its rugged design, ease of maintenance and low operating costs. It is designed to operate from remote, unprepared airstrips with austere navigational aids.
A total of 143 have so far been lost in all sorts of accidents, according to the Aviation Safety Network's statistics.
Shah reported from Kabul. Associated Press writers Slobodan Lekic in Brussels and Matthew Lee in Washington contributed to this report.