MUNICH - Secretary of State Hillary Rodham Clinton urged Egypt's pro-democracy demonstrators Saturday to support a political transition led by their military-backed government, warning that the alternative could be a takeover by radicals.

Clinton's remarks coincided with a split in the Egyptian opposition Saturday on whether to participate in nascent talks with Vice President Omar Suleiman to begin a transition to a more democratic government. Although Clinton urged opposition groups to give the process a chance, many leading figures refused to attend the discussions, repeating their demand that Mubarak leave office before any substantive dialogue begins.

Clinton seemed to be trying to salvage the talks, as the Obama administration scrambled to keep up with rapidly changing events in Egypt. After she spoke, opposition leaders there accused her of pulling back from what they had interpreted as U.S. support for Mubarak to stand down, based on President Obama's earlier call for political change in Egypt to begin "now."

Adding to the apparent dissonance in the administration's message, Frank G. Wisner, a former diplomat dispatched by the administration last week to help ease Mubarak from office, said Saturday that the Egyptian president should stay in his post for a while.

"President Mubarak remains utterly critical in the days ahead as we sort our way toward the future," he told an international security conference in Munich via video link from New York. A senior U.S. official, speaking on the condition of anonymity because of the diplomatic sensitivity of the issue, said later that Wisner was no longer acting on behalf of the administration and that his comments were personal. Wisner is no longer an envoy for the Obama administration, after his first trip yielded little progress.

Many of the demonstrators in Egypt have refused to negotiate while Mubarak remains president. Some opposition figures had expressed the hope that Mubarak would cede at least some of his powers to allow a democratic transition to proceed. But Vice President Omar Suleiman ruled that out Saturday.

Clinton, who was also speaking at the Munich conference, reiterated the administration's hope that the transition be swift but "orderly. " She praised Mubarak for agreeing not to seek reelection and for supporting the transition process being led by Suleiman.

Clinton urged the government to take more steps. But she also warned that if the transition is not carried out with deliberation, there are forces "that will try to derail or overtake the process, to pursue their own specific agenda - which is why I think it's important to support the transition process announced by the Egyptian government, actually headed now by Vice President Omar Suleiman."

Clinton did not identify the forces, but she appeared to be referring to Islamist radicals.

Some demonstrators have objected to the idea of Suleiman leading a transition, noting that he is Mubarak's intelligence chief and longtime ally.

The senior U.S. official said Clinton's remarks did not indicate that she favors a long-term role for Suleiman in running Egypt. "We recognize that Suleiman is heading this effort at dialogue. That is a fact," the official said.

He said the U.S. government was encouraged that initial negotiations had begun on a democratic transition but added that opponents should now "get engaged to test the proposition" that the government will deliver on constitutional change, free elections and other reforms.

Clinton's caution was echoed by German Chancellor Angela Merkel and British Prime Minister David Cameron, who called for a peaceful transition and warned against rushing into elections.

"When you are in a process of change . . . matters cannot move quickly enough," Merkel said, comparing the upheaval in Egypt to the collapse of the communist East German government. But she added: "We have to see to it that we set up structures that are sustainable. . . . Elections at the beginning of a transformation process is probably the wrong approach."

In his remarks from New York, Wisner told the conference that frequent calls by foreigners for Mubarak's ouster had created a "negative force" inside Egypt .

He also said there were practical reasons why it might be better for Mubarak to remain on the job.

"The Egyptian constitution is quite clear," he said. "If the presidency is vacated, then the speaker of parliament takes over, and in a couple of months you have elections. Those elections would take place under the current dispositions. Those dispositions are currently unacceptable to those protesting in the streets of Cairo today."

Therefore, he said, constitutional changes are needed, adding, "The president must stay in office in order to steer those changes through."

"The best way we can make this change is with [the government] and inside it," Wisner said.

Clinton balanced her remarks on Egypt with an appeal to Arab leaders to undertake democratic reforms before it is too late.

"The region is being battered by a perfect storm of powerful trends," she said. "A growing majority of its people are under the age of 30. Many of these people cannot find work. At the same time, they are more connected with one another - and with events around them - because of technology. And this generation is rightly demanding that their governments become more effective, more responsive and more open."

At the same time, Clinton said, "the transition to democracy is more likely to be peaceful and permanent when it involves both the government in power and a broad cross-section of the electorate."

sheridanm@washpost.com birnbaumm@washpost.com