Syria has angrily refuted the findings of a UN report that implicated Syrian officials in the murder of the former Lebanese prime minister.
The report said the attack must have had high-level backing
Rafik Hariri and 22 others died in a bomb explosion in Beirut in February.
At the UN Security Council, German investigator Detlev Mehlis called for greater Syrian co-operation to help "fill in the gaps" about the crime.
But Syria's ambassador accused his team of bias and some countries of fanning "the flames of hatred against Syria".
Fayssal Mekdad, Damascus' envoy to the UN, insisted: "This heinous crime runs counter to all the principles that Syria holds... and was against Syrian interests."
He denounced Mr Mehlis' report, saying:
- It was "very clearly influenced by the political climate" in Lebanon following the assassination
- It contained a "strange hypothesis" that Syria's deep influence in Lebanon meant it must have been involved
- Claims that Damascus had not co-operated with the investigation were "a great injustice"
The Security Council meeting adjourned, but when it reconvenes it is expected to hear calls for diplomatic action against Syria.
The US and French ambassadors said they intended to put forward a joint resolution, that is expected to demand Syria's cooperation with the Mehlis team.
French Ambassador Jean-Marc de La Sabliere said "this is a very serious concern and the council should address it".
Briefing the Security Council on Tuesday, Mr Mehlis said his investigation was incomplete and would continue until December.
He called for stepped up security for his team, saying they had received a number of "credible" threats and the high risks they ran were likely to increase.
Mr Mehlis' report, delivered last week, said there was "converging evidence pointing at both Lebanese and Syrian involvement in this terrorist act".
The report says the likely motive for Hariri's assassination was political - the former prime minister was increasingly at odds with pro-Syrian President Emile Lahoud at a time when Syria was the main power in Lebanon.
KEY UN FINDINGS
Assassins had considerable resources and capabilities
Evidence suggests both Syria and Lebanon were involved
Crime was prepared over several months
Hariri's movements and itineraries were monitored
Highly unlikely Syrian or Lebanese intelligence were not aware of assassination plot
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The plot was complex and had obviously been planned for months, Mr Mehlis said, and as such it "could not have been taken without the approval of top-ranked Syrian security officials and could not have been further organised without the collusion of their counterparts in the Lebanese security services".
US President George Bush has called for "serious pressure" on Syria - not only over Lebanon, but also over the issues of insurgents crossing from Syria into Iraq and its alleged support for Palestinian militant groups.
The Bush administration believes the UN report gives it powerful leverage in stepping up the pressure on an Arab government to which it has long been hostile, the BBC's Middle East analyst Roger Hardy says.
In an interview with Arab television, Mr Bush said force would only be used against Syria as "the last - very last - option".