Washington, Sep 13 (IANS): Pakistan has been an unreliable ally of the US in the war against terror and failed "on occasion" when forced to choose between Washington and the Al Qaeda, says US Vice President Joe Biden.

The price of Pakistan's choices has been the "loss of life of American soldiers in Afghanistan", Biden told CNN in an interview on the eve of the 10th anniversary of the 9/11 terror attacks. The full interview was aired Monday night.

Islamabad has "been very helpful in other times", he added. "But it's not sufficient. They have to get better. We need a relationship that is born out of mutual interest. And it's in their interest that they be more cooperative with us."

"We are demanding it," Biden said.

Despite troubles in Pakistan and elsewhere, the US is "getting close" to bringing about an end to organised, legitimised terrorist activities, he said.

"We have done great damage to ... Al Qaeda," Biden said. "Satellite organisations" have emerged in Somalia and elsewhere, he said, but "they are less coordinated" and "less capable".

"And we're relentless in pursuing them," he added. As a result, Americans are safer today than they were a decade ago, Biden asserted.

Regardless he cautioned that "there is always a possibility of a lone wolf" attack within the US or elsewhere.

"There's always a possibility of an incident occurring, but I do not believe there's anyone right now capable of putting together the kind of extremely complicated planned operation that took place on 9/11," he said.

Biden said he believes that in 25 years, Americans will "read about this period of terror as ... a part of a chapter in the history of this country".