"Absolutely," he said in an interview with CNN's Wolf Blitzer.
With bin Laden still at large five years after the Sept. 11, 2001, attacks and believed to be hiding along the mountainous border between Afghanistan and Pakistan, Mr. Bush disputed any suggestion that Pakistan has not done enough to hunt down terrorist leaders. Mr. Bush meets Friday at the White House, and again next week, with Pakistan's president, Pervez Musharraf.
"I view President Musharraf as somebody who would like to bring al Qaeda to justice," Mr. Bush said. "There's no question there is a kind of a hostile territory in the remote regions of Pakistan that makes it easier for somebody to hide."
In a news conference last week, Mr. Bush said he could not send thousands of troops into Pakistan to search for bin Laden without an invitation from the government. "Pakistan's a sovereign nation," Mr. Bush said then.
But in the television interview, Mr. Bush was asked whether he would give the order for American troops to kill or capture bin Laden or other terror leaders if good intelligence pointed to their whereabouts, even if it were inside Pakistan's borders.
"We would take the action necessary to bring them to justice," the president said.
On the standoff over Iran's suspected nuclear weapons ambitions, Mr. Bush said he takes Iranian President Mahmoud Ahmadinejad seriously when he says Israel shouldn't exit. Ahmadinejad has called the Nazis' slaughter of 6 million Jews a myth and said Israel should be wiped off the map or moved to Germany or the United States.
"You can't just hope for the best," Mr. Bush said. "You've got to assume that the leader, when he says that he would like to destroy Israel, means what he says. If you take — if you say, well, gosh, maybe he doesn't mean it, and you turn out to be wrong, you have not done your duty as a world leader. ... Absolutely I take him seriously."
Mr. Bush would not talk about Israeli estimates that it could take Iran only a few more months to get to the point where it could start building a nuclear bomb.
"I'm not going to discuss with you our intelligence on the subject," the president said. "But time is of the essence."
Earlier Wednesday, White House press secretary Tony Snow said Mr. Bush did not watchTuesday evening at the U.N. General Assembly.
In his remarks, which he gave only hours after Mr. Bush stood at the same podium in New York, the hard-line leader denounced U.S. policies in Iraq and Lebanon and accused Washington of abusing its power in the U.N. Security Council to punish others while protecting its own interests and allies.
Ahmadinejad insisted that his nation's nuclear activities are "transparent, peaceful and under the watchful eye" of inspectors from the International Atomic Energy Agency, the U.N. nuclear watchdog.