The Taliban insurgents who shot down a US helicopter in Afghanistan, leaving 30 American troops dead, have been hunted down and killed in an air strike, a US commander said.

General John Allen, the new chief of US-led forces in Afghanistan, told reporters at the Pentagon that "at approximately midnight on 8 August, coalition forces killed the Taliban insurgents responsible for this attack" with a bombing raid by an F-16 fighter jet.

Insurgents shot down a Chinook helicopter on Friday in the remote Tangi Valley in Wardak province, killing 30 American troops on board -- including 25 elite special forces -- in the deadliest incident of the nearly 10-year-old war for the NATO mission.

Describing the incident in detail for the first time publicly, Allen said that the helicopter had been sent in as part of an operation targeting a Taliban leader.

"The intelligence that had been generated to this point led us to believe there was an enemy network in the Tangi Valley in the Wardak province, and the purpose of this mission was to go after the leadership of that network," the general said.

When elements of the insurgent force were seen "escaping," the Chinook chopper carrying Navy SEAL commandos and Afghan soldiers was ordered in to head them off, he said.

The CH-47 was then shot out of the sky with a rocket-propelled grenade.

US forces then tracked the insurgents responsible, calling in an air strike on Monday night with an F-16, he said.

The Taliban leader originally targeted in Friday's mission was not killed, Allen said.