9:06pm UK, Thursday March 26, 2009

President Barack Obama will send an extra 4,000 US troops to Afghanistan to help train the country's forces.

President Obama at a town hall style meeting in southern California

President Obama says there must be an exit plan for Afghanistan

Mr Obama is unveiling a new US strategy for the war designed to turn the tide against a growing insurgency, the White House said.

The move to deploy an extra brigade follows President Obama's decision last month to send in 17,000 reinforcements to take on insurgents challenging the Kabul government.

The new troops will be deployed "later this year" to train local police and security forces, a defence official said.

There will be 61,000-65,000 troops in the country by mid-September with the arrival of various support units.

There's got to be an exit strategy. There's got to be a sense that this is not a perpetual drift.

Barack Obama

It doubles America's military presence in Afghanistan from December.

Outlines of Mr Obama's military blueprint have emerged in recent weeks, including plans to bolster development projects and tackle insurgent havens across the border in Pakistan.

"The President is making calls and briefing members of Congress based on the conclusion of that review, that the President will announce... at the White House," spokesman Robert Gibbs told a news conference.

The strategy is expected to expand Kabul's security forces, wooing "moderate" insurgents and stepping up civilian aid efforts.

Mr Obama has said it was crucial to set out an approach that would allow the US to eventually leave the country, after more than seven years of war.

"There's got to be an exit strategy," he told CBS television's "60 Minutes" programme. "There's got to be a sense that this is not a perpetual drift."