In an interview with CBS News, Obama said deliberations over the U.S. strategy in Afghanistan are "life and death decisions" and that he would "absolutely" fire anyone found to be leaking confidential information on the matter.
"For people to be releasing information during the course of deliberations, where we haven't made final decisions yet, I think is not appropriate," he told CBS while in Beijing during a nine-day trip to Asia.
Details of Obama's deliberations and the views of some of his national security aides have appeared for weeks in news stories. The president echoed the concerns of Defense Secretary Robert Gates about those "leaks," saying he is probably angrier than Gates about them.
"I think I'm angrier than Bob Gates about it," he said. "We have deliberations in the situation room for a reason; we're making life and death decisions that affect how our troops are able to operate in a theater of war."
Obama said in an interview with NBC News Wednesday that his strategy in Afghanistan will "put us on a path towards ending the war" and that his goal is not to pass the conflict on to the next president.
He also declined to say he trusted Afghan President Hamid Karzai, offering praise to Karzai for holding his country together but saying: "He has some strengths, but he has some weaknesses."
"I'm less concerned about any individual than I am with a government as a whole that is having difficulty providing basic services to its people," Obama said in his latest blunt assessment of the Karzai government, whose competence is an essential part of a U.S. war effort now in its ninth year.
Obama is expected soon to announce a revamping of the U.S. strategy in Afghanistan and Pakistan. He is likely to send thousands more troops into Afghanistan to stabilize the deteriorating security there.
Many times, the White House has said Obama will reveal his decision in the next few weeks. Obama did so again in a series of TV interviews, saying his announcement will come by year's end.
But there will be no drawdown of U.S. forces anytime soon. Obama has sought to repeatedly assure the world that the U.S. is not pulling out of Afghanistan, a case he plans to make to the American public.
Obama promised to tell the nation "in very clear terms, what exactly is at stake, what we intend to do, how we're going to succeed, how much it's going to cost, how long it's going to take."
He has a tough sell. Polling shows most Americans do not favor sending more troops to Afghanistan.
The Associated Press contributed to this report.