Washington (PTI): The United States has rejected Afghanistan President Hamid Karzai's demand to stop aerial bombings, saying such a step would tie the hands of the US forces in their war against terrorism in the country.

"We can't fight this war with one hand tied behind us," US Defense Secretary Robert Gates told reporters at a Pentagon press conference.

Mr. Karzai in an interview to the CNN last week demanded that the US "should stop" aerial bombings, which very often results in killing of innocent civilians.

However, Mr. Gates asserted that the US is seriously looking into the issue of civilian casualties and trying out ways how to minimize it.

"The fact of the matter is, civilian casualties since January in Afghanistan are down 40 per cent over a year ago during the same period. And US, Afghan and ISAF casualties are up 75 per cent during the same period," he said.

"So there is a tremendous effort going on our part to try and avoid civilian casualties. But figuring out how to come out better on the strategic communications side of this is an ongoing challenge for us," he said.

Earlier, US National Security Advisor General (retd) James Jones had also rejected such demand.