KABUL - A NATO helicopter crashed in Afghanistan's east on Monday but there were no apparent casualties, officials said, a reminder of the dangers of the war after 38 people were killed in an air incident two days ago, the largest single loss of foreign forces in 10 years.  

Another NATO-led International Security Assistance Force (ISAF) helicopter made a "hard landing" in Paktia province, a volatile area in Afghanistan's east, on Monday, other officials said.

"There were no casualties," ISAF spokesman Lieutenant Colonel David Doherty said. An investigation was underway but it appeared there was no enemy activity in the area at the time.

Taliban spokesman Zabihullah Mujahid claimed in a text message sent to Reuters that the Islamist group had shot down the helicopter, another Chinook, in the Zurmat district of Paktia, killing 33 American soldiers.

The Taliban often exaggerate claims in attacks against foreign troops and Afghan security forces and government targets, although they correctly identified the number killed in the weekend's Chinook crash in Wardak.

A worrying surge of military deaths is being matched by record casualties among civilians, who continue to bear the brunt of a war that appears to have become bogged down despite claims of success from both sides.

On Monday, three hundred angry Afghans took to the streets in central Ghazni province carrying the bodies of two people they claimed had been killed during a raid by ISAF troops.

Civilian casualties caused by foreign troops hunting insurgents have long been a major source of friction between Kabul and its Western backers. UN figures show such casualties hit record levels in the first six months of 2011, although it blamed 80 percent of them on insurgents.  

NATO officials are still investigating the cause of a helicopter crash two days ago that killed 38 people, including 30 US soldiers, seven Afghan commandos and an Afghan interpreter.

The Taliban claim to have shot down that troop-carrying CH-47 Chinook helicopter in central Maidan Wardak province and a US official in Washington, who asked not to be identified, said that helicopter was believed to have been shot down.

"We're still not aware of the cause of the incident, this is a very vital part of the investigation," said Brigadier General Carsten Jacobsen, senior spokesman for the NATO-led International Security Assistance Force (ISAF).

"The area in which the helicopter was operating was known to be not free of insurgents," he told a news conference.

ISAF has imposed a security crackdown on the area while the grim task of recovering the aircraft and the bodies of those killed is completed, although some residents have complained about some of the measures that have been taken.

"I can only advise (civilians) not to try to approach the site of the crash while the investigation is ongoing," Jacobsen said .