President Bashar Assad's regime, facing a last chance to cooperate in the probe of a former Lebanese prime minister's assassination, quietly weighed its next moves Tuesday as the chief U.N. investigator returned to the Middle East, where he is expected to demand that the Syrian leader and some close relatives submit to questioning.

Significantly, the increasingly isolated regime ordered no big street demonstration in support of Assad's rule, and the state-run media reacted with moderation to Monday's U.N. resolution demanding that Damascus (search) cooperate fully with a U.N. inquiry into the killing of Rafik Hariri on Feb. 14 in Beirut.

Syria will "cooperate to the utmost limit with the international organization and its various committees," said the Tishrin newspaper, which reflects government thinking. That was the hope of many Syrians, who worry that punitive U.N. measures and further isolation would have a direct impact on their lives.

"What does this all mean?" said one bewildered Syrian who did not give his name for fear of retribution. "How will it affect our jobs? Will real estate go up? Should I pack my bags and leave? I'm so confused."

Firas Tlass, a businessman and son of former Defense Minister Mustapha Tlass, said Syria must work with the international community and introduce domestic reforms to deflect pressure.

"This is no longer an Israeli-U.S. attack," he said. "This is an international attack."

The resolution came less than two weeks after lead U.N. investigator Detlev Mehlis released his report concluding it was not likely Hariri could have been killed without senior Syrian approval. Syria dominated Lebanon for 29 years, but was forced to withdraw its military in April under international pressure.

Mehlis, whose mandate has been extended to Dec. 15, has been given new authority by the Security Council — and could seek to use it immediately.

He is likely to seek to question Assad as well as Assad's brother-in-law and chief of military intelligence Assef Shawkat (search), who has been implicated in the killing, as well as the president's brother Maher Assad, who is also under suspicion.

Mehlis returned to Beirut (search) late Monday and has not spoken publicly about his agenda.

Before the U.N. action Monday, President Assad had refused Mehlis' requests to question him.

Assad has said Syria is innocent and would consider any Syrian who may have participated in the crime as a traitor. What is not clear is whether Assad would seek to protect his relatives and other senior security officers whose names appeared in the Mehlis report. Cutting them loose could lead to a power struggle that would threaten his presidency and lead to the jailing of his relatives should they be indicted.

Patrick Seale, author of a book on Assad's father, the late President Hafez Assad, said the political storm caused by the Mehlis report has given the Syrian president a golden opportunity.

"For the first time since he came to power in 2000, he has a unique chance to impose his authority on rival power centers and emerge as the real ruler of Syria," Seale wrote in Lebanon's Daily Star on Monday.

"In their different ways, both the international community and his own public are ... encouraging him to carry out a 'corrective movement' against undisciplined barons of his regime, including men close to him," Seale wrote.

Even opposition figures seem willing to give Assad breathing room. While they want the president to steer the country away from confrontation with the international community, they also have distanced themselves from opposition figure Riad Turk's call for the president to step down.

Turk, the secretary-general of the Syrian Communist Party who has spent a total of 20 years in jail, first made the call on a weekend TV program.

"The only solution is for the president to resign," he told The Associated Press. "The policies of this regime are ruining the country and leading to a confrontation with the international community."

He said Foreign Minister Farouk al-Sharaa's tirade against the resolution at the United Nations was an example of failed Syrian policies. Al-Sharaa claimed that accusing Syrian security forces of knowing in advance about Hariri's killing was like saying U.S. officials knew ahead of time about the Sept. 11 attacks, Spain knew about the 2004 train bombings or Britain knew about last summer's transit bombings.

"He should have either remained silent or pledged Syria's commitment to cooperate with the investigation," Turk said.

Michel Kilo, a Syrian dissident, said "for now" he does not agree with Turk's resignation call. "We want to know if there's anything against those people first," Kilo said.

In a show of support for Assad, a private public relations group staged a licensed protest near the U.S. Embassy on Monday. A few hundred protesters pledged to stand by Assad, seen by many Syrians as a modernist who has not been given a chance at reforms.

Mounir Hamzawi and some colleagues took a few days off from work at a private company for the protest.

"I like the president. In his eyes, I can see his belief in building this country," said Hamzawi. "But one person can't do this. He needs help. We should give him a helping hand."