US President Barack Obama meets with top military and national security advisers to discuss US strategy in Afghanistan on Wednesday as he narrows the military options he is considering to four, the White House said.

White House press secretary Robert Gibbs emphasised that any shifts in US military strategy in Afghanistan were still under discussion and that no decision had been made, contrary to earlier media reports.

“The president has yet to make a decision,” he said, adding that a final decision on a new strategy could still be weeks away.

Gibbs declined to discuss the specifics of the four options under consideration, but reports say all are likely to deal with troop increases – although by how many remains in question.

The top US and NATO commander in Afghanistan, General Stanley McChrystal, has requested 40,000 more troops to stabilise the country and definitively rout an insurgency being waged by Taliban and al Qaeda militants.

Officials have said sending 30,000 additional troops is another option under consideration, while a lesser troop increase of between 10,000 and 20,000 is also under review.

Other reports have said a maximum troop increase of up to 80,000 is also on the table.

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In an interview with US political talk show Face the Nation, Senate Republican leader Mitch McConnell said Obama could expect Republicans to “overwhelmingly” support a troop increase if one is recommended by McChrystal and General David Petraeus, the former top US commander in Iraq.

No announcement on a troop increase is expected until after Obama returns on Nov. 18 from a trip to east Asia.