President Bush and senior national security advisers grappled with strategies Wednesday to accelerate the transfer of power in Baghdad under the pressure of rising casualties and a troubling intelligence report from Iraq.

"We are in a very intense period here," said L. Paul Bremer (search), the top U.S. administrator in Iraq. The Bush administration is worried about a lack of progress by the American-appointed Iraqi Governing Council (search) toward meeting a Dec. 15 U.N. deadline for producing a new constitution and holding elections.

The administration does not intend to abandon the council, officials said, but is exploring new scenarios. One option calls for creating a smaller body within the 24-person council -- perhaps 10 people with expanded roles, or establishing one person as a strong leader of the council, a senior administration official said.

Secretary of State Colin Powell said, "We're looking at all sorts of ideas and we do want to accelerate the pace of reform." Bremer said he would go back to the council and say that "we need to pull this all together and integrate it into a plan going forward."

The administration refused to discuss publicly what was under consideration, saying the Iraqi council had to be consulted first. U.S. officials said decisions would not be imposed by the United States, but would be agreed up with the council. Bremer is taking back several scenarios for discussion, an official said. Some of the ideas that were reviewed by Bush originated from the council itself while others were suggested by Bremer to the council, the official said.

For months, the Bush administration has been saying that Iraq must first have a constitution in place and hold elections before the U.S. will relinquish sovereignty.

One option under consideration now is to name an interim Iraqi leader with authority to govern the country until a constitution can be written and elections held, an administration official said.

Bremer was hurriedly called to Washington for talks with Bush, Vice President Dick Cheney, Defense Secretary Donald Rumsfeld, National Security Adviser Condoleezza Rice and Powell. He said he would return to Baghdad with the message that Bush was steadfast in his determination to defeat terrorism and to give Iraqis authority over their own country.

"We're having some serious discussions about the best way to move forward," Powell said later.

The consultations took on greater urgency when a suicide bombing in southern Iraq killed at least two dozen people, including 18 Italians. It was the deadliest toll suffered by non-American coalition forces since the occupation began in April.

Bush, who has refrained from reacting to American casualties on a daily basis, expressed remorse. "We appreciate their sacrifices," he said. "I appreciate the steadfast leadership of Prime Minister [Silvio] Berlusconi (search), who refuses to yield in the face of terror."

Mounting U.S. casualties -- 153 soldiers killed since May 1 when Bush declared an end to major combat -- have brought criticism of the president on the eve of an election year. Many American allies have rebuffed Bush's appeal for money and troops in Iraq, and the administration is intent on holding the support it has been able to muster.

Another troubling factor behind the White House talks was a new top-secret intelligence report that painted a grim picture of the political and security situation in Iraq. It warned that Iraqis are losing faith in U.S.-led occupation forces and suggested that more Iraqis are turning to the side of insurgents fighting coalition troops, two officials said, speaking on condition of anonymity.

Bremer said that "we will face some difficult days." He refused to discuss whether Iraqis were disillusioned with the U.S. occupation. "I think the situation with the Iraqi public is, frankly, not easy to quantify."

He also said it was obvious that insurgents have been "trying to encourage the Iraqi people to believe the United States is not going to stay the course. I don't think that's going to work."

Bremer, standing outside the White House in a drizzling rain to talk with reporters, turned aside criticism of the Iraqi council. "I don't think it's fair to say the IGC is failing," he said. "They face a very difficult situation at this time" but are "more and more effective in their assumption of authorities," he said.

In New York, U.N. spokesman Fred Eckhard said that Secretary-General Kofi Annan continues to believe that "a rapid transfer of power would be good for security in the country."

"A clear timeline for the transfer of authority to Iraqis, we think, would help reduce tensions somewhat," Eckhard said.

Senate Democratic Leader Tom Daschle said he was surprised by Bremer's return to Washington. "I don't know what to make of the ambassador's visit," Daschle said. "We have not been informed as to what his purpose in coming back is."

Sen. Joseph Biden, D-Del., said, "My guess is you're going to have to transform the governing authority in order to give it more authority."

At the State Department, Powell said negative reports about Iraqi sentiment should be balanced against reports that show the Iraqi people "have faith in what's going on. They see the improvement in their lives, and they want us to stay until such time as they are able to reassume full sovereignty over their country."