WASHINGTON (Reuters) - With anti-U.S. attacks getting more brazen in Iraq, the U.S. administrator there said on Sunday he might pull staff out of a Baghdad hotel pounded by rockets that narrowly missed a top Pentagon official.

Paul Bremer, back in Washington for consultations, said he had ordered a full investigation into the attacks on the Rashid Hotel, where U.S. Deputy Defense Secretary Paul Wolfowitz was staying. He was unhurt but a U.S. soldier was killed and 15 people were wounded.

"I've asked for a complete investigation into this, obviously, and my security people are looking at it," Bremer said when asked on "Fox News Sunday" if U.S. troops and others should be pulled out of the hotel.

"Obviously, the security of our people -- and I have several hundred people who work for me staying in the Rashid -- has got to be an important factor in what we do next," he added.

The hotel houses hundreds of civil occupation officials and U.S. military forces and is close to the palace where coalition headquarters is based.

U.S. officials conceded on Sunday that attacks against U.S. forces and officials were becoming bolder and there appeared to be a more organized resistance.

Since President Bush declared major hostilities over on May 1, guerrillas have killed at least 109 U.S. soldiers and wounded many more.

Secretary of State Colin Powell said a dangerous situation existed in Iraq and the United States was working hard to get the situation under control.

"We are still in the conflict and I don't think the president ever sought to minimize that," Powell told NBC's "Meet the Press."

MORE RESISTANCE THAN EXPECTED

"We are in this insurgency situation where people strike and run and it's a much more difficult security environment," he added. "... We did not expect this would be quite this intense for so long."

Bremer said guerrillas appeared to be getting more organized and he pointed to "several hundred hard-core terrorists from the al Qaeda- and Ansar al-Islam-type groups in the country."

"They are using now more sophisticated approaches," Bremer told ABC's "This Week."

On CBS's "Face the Nation," he said the investigation in Baghdad would include what U.S. security forces in Baghdad could do to secure the hotel, including now from multiple launch rockets. Rocket-propelled grenades were used in an attack against the hotel a month ago.

"We'll have to find out exactly what this is about. But we will take all the precautions necessary to protect our people," Bremer said.

Sen. Joseph Lieberman of Connecticut, a Democratic presidential candidate, said Sunday's attack showed serious flaws in the Bush administration's handling of Iraq.

"The fact that the opposition, the terrorists, the insurgents, fired rockets at the hotel where Paul Wolfowitz was and got away with it is shocking. Why aren't we protecting the perimeter. Where did they get those sophisticated rockets?" Lieberman asked on the CBS program.