UNITED NATIONS – The brazen assassination on Monday of Rafik Hariri, which confirmed the Bush administration’s worst predictions about the Syrian occupation of Lebanon, allowed Washington to begin leading an international drive to increase the pressure and isolate the last Arab Baathist regime.

America yesterday recalled its ambassador in Damascus for consultations; increased its cooperation with France, the former colonial power in Syria and Lebanon, and united the Security Council behind a call for Secretary-General Annan to “report urgently” on the circumstances, causes, and consequences of what the council dubbed “this terrorist act.”

The Security Council was the Bush administration’s favorite venue for the initial stage of dealing with the first real crisis confronting Secretary of State Rice. At the same time, American officials and legislators planned the next stages, including increased economic isolation to complement the Syrian Accountability Act, which threatens Damascus with sanctions unless it stops supporting terrorism and ends its occupation of Lebanon.

During a press conference yesterday in Washington with Egypt’s foreign minister, Ahmed Aboul Gheit, Ms. Rice said Syria “is in interference in the affairs of Lebanon. There are Syrian forces in Lebanon. Syria operates out of Lebanon. And so when something happens in Lebanon, Syria needs to help to find accountability for what has happened there.”

France was supportive of yesterday’s action at the Security Council. President Chirac was a close friend of Hariri’s, and he supported America on resolution 1559 last fall, which called for Syria to withdraw from Lebanon.

Russia continues to support Syria. Prime Minster Sharon told foreign correspondents in Jerusalem yesterday that Israel has failed in its attempt to convince President Putin to halt a planned sale of SA-18 shoulder missiles to Syria.

The last known outsider to see Hariri alive was Terje Roed-Larsen, the U.N. envoy to the implementation of resolution 1559. An official who asked for anonymity told The New York Sun that a day earlier, on Thursday, Mr. Larsen had warned President Assad against what he termed “an outlaw behavior.”

The assassination that followed, and the strong indication of Syrian finger prints on it, raised many questions in Washington as to why Damascus failed to heed the warning. “The Baathists believe they are in control,” the president of the pro-democracy Reform Party of Syria, Farid Ghadry, told The New York Sun. Citing Russian support as well as Iranian backing of Syria, he said that the most important step right now should be to instill a sense of isolation on Damascus.

As its first step, the administration hopes to unite the Security Council behind the notion that Syria is responsible for the assassination of its powerful Lebanese rival. The council statement yesterday was designed to begin an internationally approved investigation.

“This report will give international dimension” to the probe,” France’s U.N. ambassador, Jean Marc de la Sabliere, said. U.N. officials, however, told the Sun they were not sure yet how to tackle the request to investigate.

Syria has denied involvement in the assassination. In Washington, however, a senior executive intelligence brief that circulated yesterday said the intelligence community suspected the Syrian government, although it had no hard evidence, according to three administration officials. “Everyone thinks the Syrians did this, but we can’t prove it and we will probably never prove it,” one official who had seen the intelligence memo told the Sun.

Stopping short of accusing Damascus directly for the assassination, Ms. Rice nevertheless pointed to what she called the “Syrian problem.”

In the last three months the CIA has confirmed that Damascus has laundered billions for the Iraqi insurgents aiming at American soldiers. Israeli officials told the Sun that Damascus has interfered in the peace negotiations with the Palestinian Arabs, which has been at the top of Ms. Rice’s agenda. The crisis also allowed Washington to close ranks with Paris, another of her goals.

Noting the heavy Syrian involvement in its neighbor’s affairs, Ms. Rice said, “When something happens in Lebanon, Syria needs to help to find accountability for what has happened there.” America, she added, is “united with the rest of the world in wanting a full investigation as to what happened here. But there is no doubt that the conditions created by the Syrian presence there have created a destabilized situation in Lebanon.”

Last Thursday, in his meeting with Syria’s president, Bashar Assad, Mr. Larsen passed along concerns that were expressed to him by some Lebanese opposition leaders, who said they feared for their lives. Mr. Larsen cautioned Mr. Assad that “the international community will not tolerate outlaw behavior,” according to the official.

Meeting with Mr. Larsen Friday, the multibillionaire businessman was much less concerned than other opposition leaders in Lebanon. He assumed his high international stature and especially the ties in Paris, where he has been Mr. Chirac’s financial backer and personal friend, would protect him, he had told Mr. Larsen.

In the wake of the assassination, the American ambassador to Beirut, Jeffery Feltman, yesterday met with Druze leader Walid Jumbalat, who has grown close in recent months to Hariri, forming a strong alliance in the lead to the upcoming general elections. Damascus, on the other hand, saw the first step toward diplomatic isolation, as Ambassador Margaret Scobey was recalled “for urgent consultations following the brutal murder,” a State Department spokesman, Richard Boucher, said.

At the same time, the American U.N. deputy ambassador, Anne Patterson, told the council that Washington would seek further steps against Syria in the future, according to one diplomat who participated in the close-door session. “The next step is to wait for the secretary-general’s report” on the assassination, she told reporters afterward, stressing that “he’s supposed to do that on an urgent basis.”

Congress has passed, and President Bush has signed, the Syrian Accountability Act, which specifies American economic pressure on Syria as long as it supports terrorism and continues its occupation of Lebanon. But legislators acknowledge that America’s commerce with Syria is almost nonexistent and that pressure could be increased only in accord with other nations.

“I urge the president to work with our friends and allies around the world to turn up the heat on Syria until it complies with U.N. Security Council Resolution 1559 and the Syria Accountability Act,” one of the act’s authors, Rep. Eliot Engel, a Democrat of New York, said.