Islamabad, Nov 5 (IANS) Around 20 people on board a small aircraft, most of them employees of a US oil company, were killed Friday when the private plane crashed near Karachi airport in southern Pakistan, a military spokesman said.

"The plane has been totally gutted and there are no survivors," Geo TV quoted Lieutenant Colonel Noor Alam, who supervised rescue operation, as saying.

The plane was believed to be carrying about 20 people, mostly Pakistanis, he said, adding that bodies were yet to be identified.

It was not immediately clear if there were any foreigners on board, he said.

So far, 12 bodies, gutted completely and difficult to identify, have been recovered and efforts to recover the remaining are under way, Alam said.

The accident took place at 7.15 a.m. due to engine failure, the report said.

Earlier, officials of the Civil Aviation Authority (CAA) confirmed that at least 20 people were on board and said chances of survivors were thin as the plane caught fire after the crash.

Thick smoke was seen emitting from the plane while firefighters tried hard to bring raging flames under control.

The airplane, owned by a private company, had been chartered by a US firm working on an oil field in Karachi. Two crewmembers and a technician were also on board.

A CAA official, Pervez George, told Geo TV that the aircraft was carrying company employees to an oil field at Bhit Shah in the southern province of Sindh, of which Karachi is the capital.

"It was a small plane and there were about 20 people on board. It was a privately-owned aircraft belonging to an oil company," the official said.

"Soon after they left, they contacted the airport control tower and said there was a problem in one of the engines. The plane was directed to return and soon after it crashed," he said.