The council statement also repeated calls for compliance with a five-month-old resolution that seeks Syria's withdrawal of some 15,000 troops from Lebanon.
To gain the full backing of the council, the statement did not explicitly mention Resolution 1559. But French UN Ambassador Jean-Marc de La Sabliere said it was a clear signal to Syria.
"It is not a question of pressure. It is important that this resolution is implemented, and today the Security Council has asked all parties to fully cooperate for the implementation of previous resolutions -- which means including 1559, obviously -- in favor of the political independence, sovereignty, and territorial integrity of Lebanon," de La Sabliere said.
French and U.S. diplomats, the initiators of Resolution 1559, said it was too early to assign blame for the bombing in Beirut. But the two countries have repeatedly cited Syria's presence in Lebanon as an irritant, including its role as a power broker in Lebanese politics.
Hariri resigned his prime minister post in October after Syria was seen as pressing for the extension of the term of President Emile Lahoud. Hariri had increasingly been considered an opponent of Syrian interference in Lebanese affairs.
The U.S. deputy UN ambassador, Anne Patterson, rejected suggestions that the United States was politicizing the attack in Lebanon by seeking to isolate Syria.
"This is not a political act on our part," Patterson said. "And what I think you need to [understand] here is that the Security Council has a long history of engagement on this issue and the message has been very consistent that other countries need to stop interfering in Lebanon."
Annan just last week sent his envoy, Terje Roed-Larsen, to Beirut and Damascus to press Syria for compliance with the resolution calling for a troop withdrawal.
It was not immediately clear how Annan would handle the investigation of the attack.
Earlier yesterday, Lebanese Interior Minister Suleiman Franjieh said his government would not agree to an international investigation.
He said early indications were that the 14 February attack was a suicide car bombing.
"It is almost certain that it was a suicide car [bombing]," Franjieh said. "The fact that the car was close to the convoy and not on the side of the road indicates the car was not parked, which could mean that there was an attempt to attack the convoy and it exploded. This could mean that there was a suicide [attacker] in the car."
U.S. diplomats said they have asked Security Council members to consider punitive measures to be taken against those found responsible for the attack.
Officials in Washington said the administration of President George W. Bush is also considering imposing new sanctions against Damascus. They cited reasons ranging from Syria's troop presence in Lebanon and their contention that Syria was permitting Palestinian militants and Iraqi insurgents to operate from Syria.
The United States announced yesterday that it was recalling its ambassador to Syria, Margaret Scobey. State Department spokesman Richard Boucher explained the link to Hariri's assassination.
"The reason that this particular incident is related to the [step] of recalling our ambassador, is that it -- the incident -- is a horrible thing that happened that shows the distortions of Lebanese politics that are created by the Syrian presence. It shows that the excuse, the reason, the rationale that's given for the Syrian presence really doesn't work," Boucher said.
Concern about Lebanese sovereignty was voiced repeatedly in yesterday's Security Council statement. It expressed worry about the impact of the loss of Hariri on the country's efforts to solidify its democracy.
The attack, the council said, should not be allowed to jeopardize the holding of parliamentary elections in April and May in "transparent, free, and democratic conditions."
Hariri's funeral was taking place today in Beirut, with hundreds of thousands of mourners lining the procession route.