Washington: US President Barack Obama is focused on his goal of disrupting, dismantling and defeating al-Qaeda in Afghanistan and is confident of achieving that, a top presidential aide said on Tuesday.

"The fact is that everything that we do there in Afghanistan is focused on our goal of disrupting, dismantling and defeating al-Qaeda, of stabilising Afghanistan sufficiently so that we can train up and transfer authority to Afghan security forces and withdraw our troops as we do that," White House Press Secretary Jay Carney told reporters.

"The bravery and courage of our men and women in uniform has been astounding throughout, and they continue to focus on that mission, in very difficult circumstances. So the President's focused on that," he said responding to questions on the recent developments in Afghanistan.

Obama, he said, had called his Afghan counterpart Hamid Karzai after 16 Afghan civilians were killed by a US soldier in Kandahar.

The soldier has been arrested and has been brought back to the US where he faces criminal charges.

"We made very clear both the President's feelings and our feelings about the terrible incident that occurred in Afghanistan. There is an investigation, an active investigation ongoing," he said.

Carney said the US President is focused on two things.
"One, as he made clear last week, the incident that the killing of these innocent Afghan civilians was a tragic and terrible event, and it did not represent what our military stands for, what the American people stand for," he said.

"He made that clear. There is an investigation that's taking place and, you know, we're not going to wade into that from here. Then there is the overall mission that our men and women in uniform are implementing in Afghanistan, which he is of course very focused on," he said responding to a question.