WASHINGTON — Vice President Joe Biden said this morning the Obama administration's new surge-and-exit troop strategy in Afghanistan is aimed more at wringing reforms from President Hamid Karzai than mollifying a war-weary American public.

Appearing on network news shows a day after President Barack Obama announced his plan to send in 30,000 more U.S. forces, Biden said the principal aim of the new policy is to protect the United States from further terrorist attacks while also keeping the Taliban from overrunning the country.

Democrats complained about Obama's escalation of the eight-year-old war, and Republicans are unhappy with his promise to withdraw troops in 18 months. But Congress appears nevertheless willing to approve the buildup's $30 billion price tag.

Of Karzai, Biden said the plan was an unmistakable warning.

"The purpose is to make it clear to Karzai and his government, which have up to now been unwilling to step up to the ball, to make it clear that you now have to step up to the ball," the vice president said.