Mr Murr, Lebanon’s Christian deputy prime minister and son-in-law of pro-Syrian President Emile Lahoud, was slightly injured in the blast which killed at least two people.
He suffered superficial burns and a hand injury.
The United Nations, the US, Britain, Jordan, Russia and European Union denounced the assassination attempt.
“Any form of violence to try and serve a political end, to try and intimidate people regardless of their political persuasion, is something we would oppose and oppose under any circumstances,” acting US State Department spokesman Tom Casey said.
Local media reported that the wife of the Mexican ambassador to Lebanon and Lieutenant Colonel Elias al-Bayssari of internal security, were among the nine wounded.
Mr Murr had been traveling in a motorcade through the suburb of Antelias, 10 kilometres north of the capital Beirut, when a bomb exploded in a nearby parked car.
An estimated 40 kilograms of TNT had been packed into the device.
The force of the blast completely destroyed seven cars and damaged surrounding buildings.
In the past two months, two anti-Syrians have been the target of bombings.
Former Communist leader George Hawi and journalist Samir Kassir were both killed in the separate attacks that followed the shocking assassination of former Lebanese Prime Minister Rafiq Hariri in February.
Mr Hariri’s death led to the departure of Syrian troops from Lebanon after a presence spanning nearly three decades.
Druze Muslim leader Walid Jumblatt told the private satellite channel LBCI that Mr Murr may have been the victim of a plot to silence potential witnesses in the Hariri murder case.
“There is a plot to eliminate all the witnesses or everyone able to give information on the assassination of Rafiq Hariri,” Mr Jumblatt said.
President Lahoud lashed out at the attackers, calling them “enemies of Lebanon who do not distinguish between Lebanese, whatever their allegiance and position.”
“What is important to them is to damage the country’s stability and security, in order to provoke conflict,” the president added.
But steps have been taken to consolidate the country’s political leadership.
Just hours after the latest bombing, Lebanon’s Prime Minister-designate Fouad Siniora announced the formation of a new government bringing together all the major blocs whose candidates were elected in last month’s parliamentary vote.