Q+A: U.S. troop buildup in Afghanistan

By Andrew Gray

WASHINGTON (Reuters) - The United States plans to send tens of thousands of troops into Afghanistan in the coming months -- and 10,000 more may follow in 2010 -- in an effort to roll back gains by the Taliban and other insurgent groups.

Here are some key questions about the buildup of U.S. forces in Afghanistan:

HOW MANY TROOPS WILL THE UNITED STATES AND NATO HAVE IN

AFGHANISTAN?

The United States expects to go from about 38,000 troops in Afghanistan to 68,000 by this autumn, U.S. Army General David Petraeus, head of U.S. Central Command, said on Thursday.

U.S. Army General David McKiernan, the top U.S. and NATO commander in Afghanistan, has asked for about 10,000 troops on top of that for 2010, according to U.S. officials.

Other nations, mainly NATO members, have another 32,000 troops trying to stabilize Afghanistan. The United States has asked them to increase contributions, particularly to help secure presidential elections in August.

Some nations may announce additional deployments at NATO's 60th anniversary summit on Friday and Saturday.