The US Defense Department has prepared plans for a smaller presence in Afghanistan after the White House insisted on examining the option of leaving fewer troops in the country after 2014 than was initially proposed, The Wall Street Journal reported late Friday.

The newspaper said the plans now prepared by the Pentagon call for leaving roughly 3,000, 6,000 or 9,000 US troops in the country.

Those troops would launch strikes against militants and continue training the Afghan army and police, who will be responsible for national security more than a decade after a US-led alliance ousted the Taliban regime in 2001.

US Defense Secretary Leon Panetta has said the slimmed-down force would focus on preventing Al-Qaeda, which was sheltered by the 1996-2001 Taliban government, from regaining a foothold in the war-shattered nation.

General John Allen, commander of US and NATO forces in Afghanistan, had earlier suggested leaving 6,000 to 15,000 US troops, the Journal pointed out.

Afghan President Hamid Karzai prepares to visit Washington next week to discuss the US security presence after 2014.

The United States and its allies are currently negotiating future troop commitments to Afghanistan on the basis of a formula that calls for US troops to make up two-thirds of any follow-on force, The Journal said.

According to the paper, with a smaller US troop presence, the State Department would also be forced to cut plans for large-scale diplomatic outposts across Afghanistan.

The new plans would heighten the US reliance on drones to monitor and target militants after most manned aircraft and their pilots pull out, the paper said.