Afghan President Hamid Karzai has welcomed his U.S. counterpart's announcement of the start of a phased withdrawal of U.S. troops from Afghanistan, calling it a “good” step that puts the Afghan people on the path to defending their homeland.

Mr. Karzai said Thursday it is time for the “youth” of Afghanistan to take responsibility for security in the country. But he also said Afghan security forces “must be strengthened” as international troops begin to leave.

U.S. President Barack Obama said Wednesday he has decided to withdraw 10,000 American troops from Afghanistan by the end of this year, with that figure rising to 33,000 troops by the end of 2012.

The United States currently has about 100,000 military personnel in the country, fighting a near decade-long war against Taliban insurgents that has become increasingly unpopular with the American public.

Afghan President Karzai said the U.S. decision to begin the troop pullout is the “right decision for the interest of both countries.”

A Taliban statement released Thursday dismissed Mr. Obama's decision as merely “symbolic” and called for the “immediate” and “full” withdrawal of all NATO forces from Afghanistan. The Islamist militant group also vowed to intensify its “armed struggle” until that happens.

Afghan citizens had mixed feelings about the U.S. move. Some hoped it will reduce violence that they blame on the presence of foreign troops in the country. Others worried it could plunge Afghanistan into chaos if Afghan security forces are unable to fill the vacuum created by the departure of international force.