President Obama pledged an extra $5 billion in direct aid for Pakistan today as part of a "stronger, smarter" strategy to root out insurgents in its lawless regions bordering Afghanistan.

Outlining his plans at the White House, Mr Obama appealed to Americans to see the extra funding as a "downpayment" on a safer future that would help stop al-Qaeda mounting more 9/11-style attacks on American soil.

Promising to "disrupt, dismantle and defeat" al-Qaeda and its militant allies in the Taleban, Mr Obama confirmed that a further 4,000 troops will be sent in to Afghanistan on top of the 17,000 he has already promised for an Iraq-style surge.

The latest troops will focus on training Afghan security forces. Mr Obama wants to bring the Afghan army up to 134,000 and the police force to 82,000 by 2011, although he has avoided setting any timetable for the departure of US forces.

Mr Obama also proposed the creation of an international diplomatic "contact group", including not just Nato partners but other countries with a stake in the peaceful future of the region, including Central Asian states, Iran, India, Russia and China.

"The situation is increasingly perilous," Mr Obama said as he outlined his plans in an address at the White House with Hillary Clinton, the Secretary of State, the Defence Secretary Robert Gates and other top officials lined up behind him.

"Al-Qaeda and its allies - the terrorists who planned and supported the September 11 attacks - are in Pakistan and Afghanistan. Multiple intelligence estimates have warned that al-Qaeda is actively planning attacks on the US homeland from its safe haven in Pakistan."

He appealed to Congress to endorse a bipartisan Bill sponsored by John Kerry and Richard Lugar, leading members of the Senate Foreign Relations committee, that would see direct aid to Pakistan trebled to $1.5 billion a year for the next five years. A separate Bill, which also has bi-partisan support, would set up the "opportunity zones"

"I don't ask for this support lightly," he said. "These are challenging times, resources are stretched, but the American people must understand that this is a down-payment on our future.

"I want the American people to understand that we have a clear and focused goal: to disrupt, dismantle and defeat the Taleban and al-Qaeda, and to prevent their return to either country in the future. That is the goal that must be achieved," Obama added.

Mr Obama's plans had been widely flagged in advance but the wider regional focus of the strategy was welcomed both in Afghanistan and Pakistan.

Just hours before he spoke, however, a suicide bomber demolished a mosque packed with hundreds of worshippers attending Friday prayers near the Afghan border, killing at least 48 people and injuring scores more, in the bloodiest attack in Pakistan this year.

The rising violence has called into question Islamabad's ability to counter or even keep a lid on the Islamist militants in the mountainous border region, which Mr Obama called the "most dangerous place in the world".

He added: "This is not simply an American problem _ far from it., It is, instead, an international security challenge of the highest order. Terrorist attacks in London and Bali were tied to al-Qaida and its allies in Pakistan, as were attacks in North Africa and the Middle East, in Islamabad and Kabul.

"If there is a major attack on an Asian, European, or African city, it, too, is likely to have ties to al-Qaeda’s leadership in Pakistan."

Times Recommends

• Please help: maimed children of war want their lives back
• Cabal seizes diamond riches to buy power
• White House gatecrashers got to the president