DAMASCUS, Syria -- Facing possible economic sanctions, Syria argued yesterday that it cooperated fully with a UN probe into the assassination of a former Lebanese leader and accused anti-Syrian witnesses of lying to tie the Damascus regime to the slaying.
But Saad Hariri, son and political heir of slain billionaire Rafik Hariri, praised the UN investigation and called for an international tribunal to try the alleged plotters.
''The hour of truth has come," Hariri said in televised speech from the Saudi Arabian city of Jiddah. ''The blood of the martyr Rafik Hariri and his colleagues in the march toward freedom, dignity, sovereignty will not have been shed in vain."
Damascus sought for the second day to dispute a UN report that implicated Syrian and Lebanese officials in the Feb. 14 bombing that killed Rafik Hariri, a former prime minister and opponent of Syria's domination of his country, and 20 others in central Beirut.
''All that was contained in the report is based on presumptions and allegations," Syrian Foreign Ministry adviser Riyad Dawoodi said at a news conference. ''There's no proof."
President Bush called on the UN Security Council to meet as soon as possible to hold Syria accountable for the slaying, saying that US officials were talking with UN officials and Arab governments about what steps to take.
''The report strongly suggests that the politically motivated assassination could not have taken place without Syrian involvement," Bush said during a visit to Simi Valley, Calif.
Hariri's killing provoked Lebanese to hold mass demonstrations against Syria's nearly three-decade military occupation and intensified international pressure on Damascus, leading to the regime withdrawing troops from its neighbor in April.
Dawoodi said President Bashar Assad's government was ''totally surprised at the talk of sanctions" being imposed by the UN Security Council and plans a series of diplomatic steps at the United Nations to present its own ''reading" of the investigative report.
The United States and France are readying resolutions critical of Syria for the Security Council, which is scheduled to meet Tuesday to discuss the report by the chief UN investigator, German prosecutor Detlev Mehlis.
Washington has been stepping up pressure on Assad's government, accusing it of interfering in Lebanon, letting anti-American insurgents cross into Iraq and supporting Palestinian militant groups. Syria denies doing those things.
Seeking to put another spin on Hariri's assassination, Dawoodi implied that the Arabs' longtime foe, Israel, could have been behind the killing.
He said Mehlis's report concluded that the assassination ''could not have happened without a very sophisticated means which belongs to a highly equipped security organ."
''And you just look around you, who is very well equipped?" he asked, alluding to Israel.
Dawoodi also claimed that Mehlis relied on ''witnesses that lack credibility," including a purported former Syrian intelligence officer, Zuhair Mohammed Al-Siddiq, who was arrested last week in Paris after he apparently gave false testimony to the UN team.
Referring to anti-Syrian politicians in Lebanon, he said other witnesses had political aims in what they told investigators.
''I believe the report needs to be put aside and the investigation continued till (the investigators) have convincing facts," Dawoodi said. ''This report could not be used in court."
One of the report's key allegations is that Syrian Foreign Minister Farouk al-Sharaa lied in a letter to investigators, though it didn't give details.
Dawoodi disputed the claim, saying a four-line letter that al-Sharaa wrote to the UN team reflected ''exactly what happened" at a meeting between Hariri and Assad in August 2004.
Lebanese politicians who oppose Syria's involvement in their country's affairs have claimed that Assad threatened Hariri at the meeting, which was the last held between the pair. Assad's government denies that.
Despite its complaints, Dawoodi said, Syria will keep cooperating with the probe, which has been extended until Dec. 15, ''but we'll see what is the extent of this cooperation."
Saad Hariri, who heads the largest bloc in Lebanon's parliament, called the UN report ''a passage from the truth to justice."
In his first official comment since the report was released, the slain leader's son called for an international tribunal to try the alleged killers.
''Reaching justice presents the Arab and international community with additional responsibilities that prompt us to urge them to continue all aspects of the investigation in the crime and refer it to an international court that is capable of punishing the criminals," said Hariri, who is among a group of Lebanese politicians temporarily living abroad because of fears of violence at home.