More troops to Afghanistan by summer-U.S. defense secretary

Gates, visiting a NATO military base in the southern Afghan city of Kandahar, said he was working to meet a request for more forces from U.S. General David McKiernan, the alliance's top commander in Afghanistan.

"We're going to try and get two additional brigade combat teams, in response to his request, into Afghanistan by summertime," Gates, who will stay in his post in the administration of President-elect Barack Obama said, Reuters reported.

According to media reports Gates was also said that he would not have to cut troop levels further in Iraq to free up at least two of those three brigades for Afghan duty.

There are some 65,000 foreign troops in Afghanistan, about 31,000 of them from the United States, struggling to stabilize the country in the face of a growing Taliban insurgency.

Gates also said the incoming administration of Barack Obama should be careful in undertaking a build-up of foreign troops in a country that has often proved to be their undoing, AFP reported.

"The history of foreign military forces in Afghanistan, when they have been regarded by the Afghans as there for their own interests and as occupiers, has not been a happy one," he said.

"The Soviets couldn't win in Afghanistan with 120,000 troops and they clearly didn't care about civilian casualties. So I think we have to think about the longer term in this," he added.

A U.S.-led invasion following the Sept. 11 attacks on the United States toppled the hardline Islamist Taliban from power in Afghanistan in late 2001.