British Prime Minister Gordon Brown has called on Pakistani President Asif Ali Zardari to take tougher action against al-Qaeda leader Osama Bin Laden.

"Brown called President Zardari yesterday, he expressed support for what Pakistani forces are doing against the Pakistani Taliban but said he wanted to see tougher action against the leadership of al-Qaeda," a British official said on Monday.

In television interviews on Sunday, Brown also questioned why there have been no leads on bin Laden and his second-in-command Ayman al-Zawahri.

"People are going to ask why, eight years after 2001, Osama bin Laden has never been near to being caught... and what can the Pakistan authorities do that is far more effective," Brown told Sky news.

Brown also underlined that the fight against the Taliban in Afghanistan needs to be matched by more effective action by Islamabad and Pakistani forces on their side of the border.

"Al-Qaeda has a base in Pakistan, that base is still there," Brown alleged, adding that "they are able to recruit from abroad."

"The Pakistani authorities must convince us that they are taking all the action that is necessary to deal with that threat," he said.

The news comes a day after a US Senate report revealed that military leaders allowed bin Laden to 'walk unmolested out of Tora Bora' when he was within reach of US troops.

The British premier faces plunging popularity at home over the deployment of British forces to war-torn Afghanistan.

Ninety-eight British service personnel lost their lives in 2009 alone, making it the bloodiest year for UK troops since the Falklands War in 1982.

An increasing majority of Britons want the country's 9,000 troops out of Afghanistan within a year, according to the latest opinion polls. However, Brown announced a decision to deploy 500 more troops in Afghanistan on Monday.

Some 71 percent of Britons would back a phased withdrawal of British forces within 12 months, a poll conducted by The Independent showed.

RZS/JG/MMN