Afghanistan's interior minister says there may be between 10,000 and 15,000 Taliban fighting inside his country, and the insurgent group is operating across about 17 provinces.

Mohammad Hanif Atmar offered a rare estimate of the size of his government's most organized and potent opponent during a visit to Washington. A large delegation of senior Afghan officials was in the U.S. capital this week, along with a delegation from Pakistan.

Both groups were weighing in as the new Obama administration forms a new strategy for the war in Afghanistan and a related policy for Pakistan. Afghan officials say they told their hosts that a new strategy must include better cooperation from Pakistan, where Taliban and other militants have command operations.

The White House announced this month that it intended to send an additional 17,000 troops to Afghanistan.

Army Gen. David McKiernan, the top U.S. commander in Afghanistan, predicted at the time that the bolstered numbers of U.S. soldiers in Afghanistan — about 55,000 in all — will remain near those levels for up to five years.

McKiernan said the extra Army and Marine forces will be in place by the summer, primed for counterinsurgency operations against the Taliban but also ready to conduct training with Afghan police forces.

McKiernan said what the surge "allows us to do is change the dynamics of the security situation, predominantly in southern Afghanistan, where we are, at best, stalemated.

"I'm not here to tell you that there's not an increased level of violence, because there is," he said.

Another 10,000 U.S. soldiers could be headed to Afghanistan in the future as the Obama administration decides how to balance its troop levels with those from other nations and the Afghan army. The White House has said it will not make further decisions about its next moves in Afghanistan until it has completed a strategic review of the war, in tandem with the Afghan government.

Afghan and Pakistani officials met separately this week, as well as in three-way sessions with U.S. hosts. Obama has named a new envoy to manage an overhaul of U.S. policy toward a region Obama calls the real central front against terrorism.