New York ? NBC fired journalist Peter Arnett on Monday, angered that he had given an unauthorized interview with state-run Iraqi TV saying the American-led war effort initially failed because of Iraq’s resistance.

Arnett apologized for his “misjudgment,” but added: “I said over the weekend what we all know about this war.”

Meanwhile, the Pentagon was investigating whether Fox News Channel reporter Geraldo Rivera endangered troops by revealing the plans of a military unit in Iraq in advance. Rivera denied reports that he had been expelled from the country.

Arnett, who won a Pulitzer Prize reporting in Vietnam for The Associated Press, gained much of his prominence from covering the 1991 Gulf War for CNN. One of the few American television reporters left in Baghdad, his reports were frequently aired on NBC and its cable sisters, MSNBC and CNBC.

NBC was angered because Arnett gave the interview Sunday without permission and presented opinion as fact. The network initially backed him but reversed field after watching a tape of his remarks.

The network said it got “thousands” of e-mails and phone calls protesting Arnett’s remarks — a thousand e-mails to MSNBC President Erik Sorenson alone.

“When I heard he had given an interview to Iraqi TV, I immediately thought it was about as bad a judgment that a reporter in the field could make,” Sorenson said. “I held out hope initially that maybe he had given the interview at gunpoint or there was some extenuating circumstance.”

In the interview, shown by Iraq’s satellite television, Arnett said the United States was reappraising the battlefield and delaying the war, maybe for a week, “and rewriting the war plan. The first war plan has failed because of Iraqi resistance. Now they are trying to write another war plan.”

Arnett said it was clear that, within the United States, opposition to the war was growing, along with a challenge to President Bush about the war’s conduct.

Immediate job offer

A British tabloid said today it has hired Arnett as a reporter. “Fired by America for telling the truth,” the Daily Mirror said in a Page 1 headline.

Reporter Peter Arnett is shown on Iraqi television in this frame shot from CNN. Arnett, covering the war from Baghdad for NBC, was fired by the network Monday but hired by a British tabloid.

“I am still in shock and awe at being fired,” Arnett wrote for the newspaper, which is vehemently opposed to the war.

Arnett, speaking Monday on “Today,” said he wanted to apologize to the American people.

“I gave some personal observations, some analytical observations, which I don’t think are out of line with what experts think,” he said. “But clearly I misjudged the firestorm.”

Arnett went to Iraq this year not as an NBC News reporter but as an employee of the MSNBC show “National Geographic Explorer.” When other NBC reporters left Baghdad for safety reasons, the network began airing his reports. Arnett was also relieved of his duties at National Geographic Explorer.

Geraldo decries ‘lies’

Fox’s Rivera, traveling with the 101st Airborne Division in Iraq, revealed tactical information and at one point told about an attack two hours before it took place, according to sources at the U.S. Central Command who asked not to be identified.

Fox’s rivals, CNN and MSNBC, both reported Monday that Rivera had been kicked out of the country.

“During a live broadcast, Geraldo drew a map in the sand of where that unit was going. Not exactly what you’re supposed to do out there,” CNN anchorman Leon Harris said.

Shortly thereafter, Rivera delivered a report via satellite phone saying he was 60 miles from Baghdad. In the report, which first aired at 10:30 a.m. CST, Rivera labeled reports of his ouster “a pack of lies” spread by his former colleagues at NBC.

“It seems to me like some rats at my former network are spreading lies about me,” he said. “They can’t compete fair and square on the battlefield, so they’re trying to stab me in the back. It’s not the first time.”

Rivera said he intended to ride into Baghdad in search of Saddam Hussein, “the Iraqi Hitler.”

Pentagon spokesman Bryan Whitman said that while Rivera was not embedded with any military unit, any violations of embedding rules were taken very seriously.

“I have been in contact with the news organization and assured they are taking it seriously,” Whitman said. “We will make an appropriate determination once we have evaluated all of the facts.”