A combative President Assad warned his people of more crises to follow for Syria and rejected international accusations of Syrian complicity in the killing and launched a tirade against its enemies and Beirut's new leaders.
"I always said Syria is innocent," Mr Assad said. "I say we are very close to the absolute truth that we are innocent ... Syria is not implicated as a country or as an individual."
He also vowed that Damascus, despite its distrust of the process, would fully cooperate with a UN probe into the February 14 murder of Hariri in a Beirut bomb blast.
US accusations
But the United States again accused Syria of failing to abide by UN resolutions, while the Lebanese cabinet voiced its surprise at a vitriolic attack by Mr Assad on Prime Minister Fuad Siniora.
"We think it's appalling," said US State Department spokesman Adam Ereli.
"Assad's remarks today can only be seen as a defiance of those resolutions."
"Let's remember, first of all, that the international community has made it clear to Syria that it must first fully cooperate with the Mehlis investigation and, second, cease all interference in Lebanese domestic affairs," Mr Ereli said.
The speech also failed to impress French President Jacques Chirac, whose country was a co-sponsor of a UN Security Council resolution warning Syria of further international action if it fails to comply.
If Mr Assad "continues to refuse to listen, or understand, then it will become necessary to move to another level, which is that of sanctions", Mr Chirac said.
Assad pessimistic
In his hour-long speech, Mr Assad voiced pessimism over the results of the probe.
"Whatever we do or say to cooperate, the response is just going to be in a month that Syria is not cooperating. We have to be realistic, Syria is being targeted."
On Wednesday, Syria said it has slapped travel bans on nationals named in an interim report released last month on the probe of the UN commission whose mandate runs out in mid-December.
According to Lebanese newspapers, the six officials include Assef Shawkat, Mr Assad's brother-in-law and head of military intelligence, who was cited in witness testimony in a confidential version of Mr Mehlis's report.
"Instead of looking for the truth, the commission is relying on a false witness," seethed Mr Assad.
"What is happening today has nothing to do with the assassination of Rafiq Hariri because they are looking for a false truth," he said, arousing applause from the audience and thousands of flag-waving students assembled outside.
The speech at Damascus University came amid mounting pressure to allow top Syrian officials to be grilled by the UN probe but Assad's comments did not reveal whether Damascus was prepared to accept this request.
Instead he lashed out at the Lebanese government which swept to power to replace their pro-Syrian predecessors in the aftermath of the murder.
Siniora appeal
Mr Assad slammed Mr Siniora as a "slave" of his masters, in a thinly veiled reference to Western countries.
"We asked Siniora to work to preserve good relations with Lebanon but some of those who are in power are hostile to Syria and accept that their country serves as a passage point for plots."
Lebanon's cabinet said it rejected Mr Assad's attack in a statement issued after a meeting boycotted by five Shiite ministers in a sign of resurgent political divisions.
In apparent response to criticism of his leadership abilities since taking over as president in 2000 on the death of his father Hafez al-Assad, he said.
"Bashar al-Assad will not be one to lower his head to anyone."
He accused Washington of sabotaging Syrian efforts to normalise ties with Baghdad.
"We condemn the terrorist activity in Iraq ... The occupation forces cast the blame on others and the target is Syria," he said, referring to US charges Damascus was turning a blind eye to cross-border infiltration by insurgents.
Efforts to set up diplomatic ties were being "sabotaged by the occupiers", said Mr Assad, who renewed an invitation for Iraqi President Jalal Talabani and Prime Minister Ibrahim Jaafari to visit Damascus.
Straw chastises Syria
British Foreign Minister, Jack Straw, who arrived in Baghdad after stopping off in Amman to visit one of the bomb sites, has called on Syria to step up its efforts to control its borders and prevent fighters from entering Iraq.
"There is great concern in the European Union about the need for Syria to take much more action to control terrorism in its territory and from its territory," Mr Straw told a news conference held jointly with Iraqi Prime Minister Ibrahim Jaafari.
"Syria should be more serious about controlling its borders and preventing the penetration of terrorists into Iraq," Jaafari said, adding Syria should close "any (terrorist) training camps that they have inside their land."