It had prompted criticism from Democrats, Republicans and the government of Pakistan.

He told his Elko audience, "I made a simple proposition that I'd like anybody here to challenge me on."

"If those folks who killed 3,000 of us are training to act again, and we have actionable intelligence and can take them out, and the (Pakistani) government won't act, then we should act," he said.

Obama also sought to clarify his assertion that nuclear weapons would be "off the table" in such an attack. His top rival, New York Sen. Hillary Clinton, pounced on the comment, saying leaders should not discuss hypotheticals involving nuclear weapons.

Obama portrayed the question and Clinton's critique as absurd.

"Everybody knows that you'd use conventional weapons in those circumstances ... every military expert knows that you'd never use nuclear weapons in that situation," he said.

He said the U.S. needs to end the war in Iraq and go after the real terrorists.

"We are spending $275 million a day in Iraq and I want to get that money back and spend some of it here in Elko," he said.

He also told the crowd that America's dependency on oil has the nation paying for both sides of the war on terror.

Obama appeared pleased by the response he received in Elko. He told the crowd that he is drawing more support from independents and Republicans than the other Democratic candidates are.

"I suspect some of you are Republicans who decided to come here because you had nothing better to do on a Sunday afternoon," he said.

He was the third presidential candidate to visit this prosperous northeastern Nevada mining city of 18,000 this year.

Candidates of both parties suddenly have discovered Elko in their quest for votes in the party caucuses next Jan. 19.

Republican Sen. John McCain of Arizona stopped here in May and New Mexico Gov. Bill Richardson was the first Democrat to visit, on July 13. Republican Mitt Romney, a former governor of Massachusetts, is due on Aug. 13.

So far, however, Obama is the only candidate to open a campaign office in Elko, a fact he emphasized to his audience Sunday night.

"I want to spend most of my time here listening," said Obama during the 65-minute town hall meeting. "I don't presume to know everything about rural Nevada."

He repeatedly asked people to talk about rural issues, but the Elko crowd posed questions that were typical of what candidates are asked in other parts of the country. Audience members asked about the war, health care, illegal immigration and the No Child Left Behind law.

"Everybody should have health care," Obama said. "If you are paying my salary, you should have health care insurance as good as mine. My mother died of cancer. None of the doctors talked to each other. It was like we had to coordinate the case."

Regarding illegal immigrants, he said, "We aren't going to ship the 12 million people out of here. It would take all of our law enforcement, fill up our jails and fill all of our school buses for the next 10 years."

Illegal immigrants must pay a fine, learn English and go to the back of the line on a path to citizenship, he said.

He said people need to keep in mind why the vast majority of illegal immigrants came to the United States, however.

"If Canada was paying a hundred bucks an hour for jobs, how many of us would be pouring across the border to Canada?"

As for No Child Left Behind, he said, "Don't tell the schools to improve if you don't give them anything to improve with."

Only one resident, Don Miller, posed an Elko-specific question. Miller asked Obama if he would vote to rewrite the Mining Law of 1872 and support an 8 percent royalty on mineral revenues.

"I want to make sure mining thrives and the federal government is adequately compensated," Obama said, adding that he wanted to know more about the issue.

Miller told him an 8 percent royalty would shut down most mines and he advised Obama to leave the law as it is.

"I am still in the learning phase of this process," Obama said. "I don't want to destroy jobs and the interests in this area of Nevada."

He advised those who are cynical about government to look to his campaign and check his record.

He said they would learn that he delivers on his promises.

"You just keep on truckin'," one supporter shouted.

The Associated Press contributed to this report