Newspapers said the attack was a message to US President George W. Bush during his visit to the region and was aimed at undermining efforts to end Lebanon’s long-running presidential crisis.

Arab League chief Amr Mussa was due back in Beirut on Wednesday in a fresh bid to resolve the deadlock between pro- and anti-Syrian political factions that has left the country without a president for almost two months.

Tuesday’s blast left three people dead and 26 injured, including the Lebanese driver of the US embassy car and an American passer-by on a brief visit to Lebanon, security officials said.

Security was tight around the capital with army checkpoints set up in many areas as Lebanese and US investigators gathered evidence at the blast site on a seafront road in Dawra, a Christian suburb on the northern edge of Beirut.

It was the first anti-American bombing in Lebanon since the 1980s, when US military and diplomatic missions were hit and Islamic fundamentalists seized several American hostages at the height of the civil war.

The bombing, the latest in a string of political attacks in Lebanon in recent years, drew widespread condemnation with US Secretary of State Condoleezza Rice expressing “outrage” and calling it an act of terrorism.

The US embassy said it was limiting the movement of its personnel following the attack and advising American nationals to exercise extreme caution.

“The bomb targeting a vehicle from the US embassy was a message to Bush,” said the Ad-Diyar newspaper, which is close to the opposition backed by Syria and Iran.

Other newspapers and politicians said it was clear that the 15-kilo (33 pound) bomb, which had been planted on the side of the road, was aimed at torpedoeing efforts by the Arab League to end Lebanon’s political stalemate.

“The bombing targeted a vehicle from the US embassy or the convoy of the Arab solution?” the pro-opposition As-Safir questioned, referring to an Arab League plan to end the crisis between the country’s Western-backed government and the Hezbollah-led opposition.

Lebanon has been without a president since November 23, when pro-Syrian head of state Emile Lahoud stepped down with no elected successor.

Mussa was due back in Beirut later Wednesday on his second visit this month to try and prod feuding politicians to agree to the Arab initiative that calls for the election of army chief General Michel Sleiman as president.

The plan also calls for the formation of a national unity government in which no one party has veto power and the adoption of a new electoral law.

Parliament is due to meet on January 21 for a presidential vote but 12 previous sessions have been cancelled.

Although the ruling coalition has given the plan its full backing, Hezbollah is insisting the opposition be granted a third of the seats in a new government so as to have a veto over key decisions.

Mussa said on Tuesday the bomb attack was clear evidence of the urgency to end Lebanon’s political crisis.

He said he would be travelling to Damascus on Thursday for talks with Syria’s leadership which has been accused of standing in the way of ending the crisis.

Several politicians and newspapers however are already predicting that the Arab plan is doomed to failure.

The leading Arabic newspaper An-Nahar said no election was likely to take place until after the March Arab summit in Damascus or even after legislative elections due in Lebanon in early 2009.