`I was not going to extend this forever war'

• Joe Biden said ending the war in Afghanistan marked the end of the era of America “remaking nations.”

The U.S. president indicated a retreat in the United States' role as the world policeman as he offered a defiant justification for his decision to pull out.

Biden said the cost of the war had been too high in terms of lives and money.

In an address to the nation from the White House Tuesday he said: “This decision about Afghanistan is not just about Afghanistan. It's about ending an era of major military operations to remake other countries.

“I was not going to extend this forever war, and I was not extending a forever exit.”

He added: “Yes, the American people should hear this. Three hundred million dollars a day for two decades. What have we lost as consequences in terms of opportunities? I refuse to continue a war that was no longer in the vital national interests of our people.”

Biden said 800,000 Americans had served in Afghanistan and he listed the numbers of dead and injured for the American public.

“We've been a nation too long at war.”

The president attacked critics who said America could have stayed in Afghanistan with a small military presence. He said: “There is nothing `low grade' or `low risk' about any war.”

Biden took responsibility for the tumultuous U.S. evacuation, saying it was the best available option after a leading Republican foe described it as a self-inflicted wound that had made America less safe.

In his first remarks since the final pullout, Biden said 90 per cent of Americans who wanted to leave were able to do so, and that Washington had leverage over the Islamist militants to ensure 100 to 200 others could also depart if they wanted to.

“I take responsibility,” he said, adding that the United States was far from done with Afghanistan and, in particular, with Islamic State adherents in the country.

The Taliban now control more territory than when they last ruled before they were ousted in America's longest war, which took the lives of nearly 2,500 U.S. troops and an estimated 240,000 Afghans, and cost some $2 trillion.

U.S. Senate Republican leader Mitch Mcconnell said Americans had been abandoned behind enemy lines.

“This was a disgraceful and disastrous departure that will allow the Taliban and al-qaida to celebrate the 20th anniversary of 9/11 by having complete control of Afghanistan,” he said at a business forum in Ashland, Ky. “We are less safe as a result of this self-inflicted wound.”