The UN Security Council has requested an urgent report into the 'terrorist' assassination of Lebanon's former prime minister, and again pressed Syria to pull its forces out of the country.
The US earlier recalled its ambassador to Syria for consultations, the State Department said.
In Lebanon, crowds mourning Rafik al-Hariri shouted anti-Syrian slogans as opposition leaders bluntly implicated Damascus in the murder.
Syrian workers were attacked in Mr Hariri's home town, Sidon.
Mr Hariri was a leading opponent of Syria's continued military presence in the country.
But Syrian Vice President Abdel-Halim Khaddam was among those who filed into Hariri's Beirut home to pay condolences, and in Damascus, state media said Syria had condemned his killing.
Mr Hariri's funeral will take place tomorrow at the Mohammed al-Amin Mosque in Beirut's city centre.
The Hariri family is reported to have asked the Lebanese government to stay away.
Three days of mourning for the former leader have begun following his assassination yesterday.
Beirut is in a high state of alert after the massive car bomb attack, which was the first major violence in the city for 15 years.
Checkpoints have been set up around the city.
A previously unknown group said yesterday it had carried out a suicide attack against Hariri, who also held Saudi citizenship, because he supported the Saudi royal family.
Hours later Lebanese security forces said they had raided the Beirut home of a man they identified as a Palestinian who had read the videotaped claim of responsibility. A security source said Ahmed Tayseer Abu Adas was not in the house.
Hundreds of protesters took to the streets of Hariri's southern hometown Sidon, shouting slogans blaming Syrian President Bashar al-Assad for his death. Similar protests took place in Beirut on a smaller scale.
