President George W. Bush said on yesterday 3,200 more US troops being deployed to Afghanistan will help Nato forces launch a spring offensive against the Taliban.

The Pentagon announced on Wednesday that a US Army brigade of 3,200 troops will now go to Afghanistan instead of Iraq in order to maintain higher troop levels against the Taliban.

In a speech before the American Enterprise Institute, Mr Bush said he was asking the US Congress for $11.8 billion over the next two years to help the Afghan government of President Hamid Karzai.

"I've ordered an increase in US forces in Afghanistan. We've extended the stay of 3,200 troops now in the country for four months and will deploy a replacement force that will sustain this force for the foreseeable future," Mr Bush said.

"These forces and funds are going to help President Karzai defeat common enemies," Mr Bush said. Nato, US and Taliban commanders have warned of an increase of fighting in the spring when the snow melts, after the bloodiest year since the hard-line Islamists were ousted by a US-led coalition in 2001.

"This spring there's going to be a new offensive in Afghanistan, it's going to be a Nato offensive, and that's part of our strategy - relentless in our pressure," Mr Bush said. For Nato to succeed in Afghanistan, Mr Bush said member nations "must provide commanders on the ground with the troops and the equipment they need."