John D. Negroponte was sworn in as U.S. ambassador to Iraq yesterday, saying his mission was to help the country defeat terrorists and "criminal elements who oppose a free Iraq," and to promote economic development and democracy.

The seasoned ambassador -- Baghdad will be his fifth post, including his most recent assignment as the U.S. representative at the United Nations -- said, "The United States needs partners to advance our values and interests in the world."

At the swearing-in at the State Department, Secretary of State Colin L. Powell implied anew that there may be additions to the 32-nation coalition that is engaged in peacekeeping and fighting insurgents in Iraq.

"Dozens of nations have contributed to and sacrificed for the sake of a new and free Iraq," Powell said. "And those contributions will continue. I know that the Iraqi people will welcome new partners."

In an interview on the "Glenn Beck Program," which is carried by 160 radio stations, Powell said Iraqis are not ready to take care of their security. "If we could get more forces, that would be fine," he said.

Earlier in the day, Negroponte, appearing on ABC's "Good Morning America," said the purpose of U.S. programs was "to enable, to empower the Iraqis to take more and more responsibility."

"Even those who might have qualms about how we got into the situation in Iraq would agree that we have to have a solid plan going forward, that we can't just up and leave and leave the country in chaos," he said.

Negroponte said: "I'm not arguing or suggesting that the situation be turned around completely overnight, nor that every problem can be solved right away. Sometimes, as Americans, we tend to be a bit impatient, but I think it's possible to get the trend moving in the right direction."

He said neither he nor his wife and children were oblivious to the dangers of a post in Baghdad, but felt it his duty to take the job when asked by President Bush.

"You think about it, you think about what's prudent and you don't take silly chances," he said.