Afghan peace talks with Taliban are dead: Trump

President Donald Trump has said the Afghanistan peace talks with the Taliban are "dead", saying the United States had hit the group harder in the last four days than anytime in 10 years.

"They (talks with the Taliban) are dead. As far as I'm concerned, they're dead," Trump told reporters at the White House on Monday.

The president had stunned the world on Saturday when he announced the cancellation of a secret meeting with the Taliban and Afghan President Ashraf Ghani at Camp David near Washington. It came after the Taliban claimed responsibility of an attack in Kabul last week, in which an American soldier were among the dead.

"They (the Taliban) thought that (they) had to kill people in order to put themselves in a little better negotiating position.... You can't do that with me," Trump said while responding to a question about his decision to cancel the talks.

"So, they dead as far as I'm concerned," he said. "We have hit the Taliban harder in the last four days than they have been hit in over 10 years. So that's the way it is." Trump said the decision to invite the Taliban to Camp David was his, and so was the call to cancel it.

Justifying the move, the president underlined that he did not want the meeting to happen under circumstances "where they (Taliban) go around and try and make themselves a little bit more important by killing a soldier and also a total of 12 people".

The Taliban, Trump said, did a mistake. "We want to get out (of Afghanistan). But we'll get out at the right time," he said.

"We have been serving as policemen in Afghanistan, and that was not meant to be the job of our Great Soldiers, the finest on earth," Trump tweeted earlier. "Over the last four days, we have been hitting our Enemy harder than at any time in the last ten years!"