Kabul  - Civilian casualties from US and NATO airstrikes in Afghanistan tripled last year to more than 500 and are eroding public support for the government, Human Rights Watch said Monday.

The New York-based organization's report issued Monday also condemned the Taliban's use of "human shields" during their attacks against the combined forces as "violation of the laws of war."

"Civilian deaths in Afghanistan from US and NATO airstrikes nearly tripled from 2006 to 2007, with recent deadly airstrikes exacerbating the problem and fuelling a public backlash," the group said.

The report said most of those civilian deaths came during the rapid-response strikes called in by troops engaged in combat with insurgents, it said.

"The US needs to end the mistakes that are killing so many civilians," Brad Adams, Asia director of Human Rights Watch, said in the statement.

"Mistakes by the US and NATO have dramatically decreased public support for the Afghan government and the presence of international forces providing security to Afghans," Adams said.

Hundreds of Afghanis protested the reported killing of 90 civilians in a US airstrike in Azizabad village in western Herat province on August 22. Similar demonstrations took place against the foreign forces in other parts of the country including capital Kabul in the past month.

Meeting with villagers in Azizabad, Afghan President Hamid Karzai admitted his relations with US and NATO forces have strained over mounting civilian deaths, and he vowed to bring the perpetrators to justice.

In the first seven months of 2008, at least 367 civilians died during attacks by various insurgent forces and 173 died during US and NATO operations, the report said.

At least 116 of 929 Afghan civilians were killed by international forces in 2006, while 321 of the 1,633 civilians killed in 2007 caused by US or NATO airstrikes, it said.

"Thus, civilian deaths from US and NATO airstrikes nearly tripled from 2006 to 2007."

The report also blamed Taliban militants for deploying their forces in populated villages, at times with the specific intent to shield their forces from counterattack.

"Human Rights Watch found several instances where Taliban forces purposefully used civilians as shields to deter US and NATO attacks," the report said.

The group called on US and NATO forces that together have some 70,000 troops in Afghanistan to "address the rising civilian death toll from unplanned airstrikes."

The reports also criticized the US commanders for denying responsibility for the civilian deaths immediately following the operations and prior conducting any investigations.

"US investigations conducted have been unilateral, ponderous, and lacking in transparency, undercutting rather than improving relations with local populations and the Afghan government," it said.

"Civilian deaths from airstrikes act as a recruiting tool for the Taliban and risk fatally undermining the international effort to provide basic security to the people of Afghanistan," Adams warned. (dpa)