Washington: Vice President Joe Biden has said Pakistan has been an "unreliable ally" of the US in the war against terror and asserted that it was in their interest to co-operate more.

Biden, on the eve of the 10th anniversary of the 9/11 terror attacks, said Pakistan has failed "on occasion" when forced to choose between the US and al-Qaeda.

The price of Pakistan's choices has been the "loss of life of American soldiers in Afghanistan," he said.

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," he said.

The US-Pak relations had dipped to the lowest level since the May 2 US military operation that killed al-Qaeda leader Osama bin Laden in Pakistan's garrison city of Abbottabad.

Pakistani authorities insist they did not know bin Laden's location.

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

"We have done great damage to ... al Qaeda," he 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 on Monday than they were a decade ago, Biden asserted.