The Illinois senator warned Pakistani President Gen. Pervez Musharraf that he must do more to shut down terrorist operations in his country and evict foreign fighters under an Obama presidency, or Pakistan will risk a U.S. troop invasion and losing hundreds of millions of dollars in U.S. military aid.

"Let me make this clear," Obama said in a speech prepared for delivery at the Woodrow Wilson International Center for Scholars. "There are terrorists holed up in those mountains who murdered 3,000 Americans. They are plotting to strike again. It was a terrible mistake to fail to act when we had a chance to take out an al-Qaida leadership meeting in 2005. If we have actionable intelligence about high-value terrorist targets and President Musharraf won't act, we will."

The excerpts were provided by the Obama campaign in advance of the speech.

Obama's speech comes the week after his rivalry with New York Sen. Hillary Rodham Clinton erupted into a public fight over their diplomatic intentions.

Obama said he would be willing to meet leaders of rogue states like Cuba, North Korea and Iran without conditions, an idea that Clinton criticized as irresponsible and naive. Obama responded by using the same words to describe Clinton's vote to authorize the Iraq war and called her "Bush-Cheney lite."

The speech was a condemnation of President Bush's leadership in the war on terror. He said the focus on Iraq has left Americans in more danger than before Sept. 11, 2001, and that Bush has misrepresented the enemy as Iraqis who are fighting a civil war instead of the terrorists responsible for the attacks six years ago.

"He confuses our mission," Obama said, then he spread responsibility to lawmakers like Clinton who voted for the invasion. "By refusing to end the war in Iraq, President Bush is giving the terrorists what they really want, and what the Congress voted to give them in 2002: a U.S. occupation of undetermined length, at undetermined cost, with undetermined consequences."

Obama said that as commander in chief he would remove troops from Iraq and putting them "on the right battlefield in Afghanistan and Pakistan." He said he would send at least two more brigades to Afghanistan and increase nonmilitary aid to the country by $1 billion.