A pair of bombs have exploded minutes apart on two minibuses travelling near a Lebanese Christian mountain town this morning, killing at least three people and wounding 20 more.

The attack, on a busy commuter road near the town of Bikfaya, northeast of Beirut, came of the eve of a major rally by pro-government supporters to mark the second anniversary of the assassination of Rafik Hariri, the former Prime Minister.

World governments denounced the blast, with Margaret Beckett, the British Foreign Secretary, saying it was clearly designed to heighten tensions in the country at a time of acute political sensitivity. British diplomats expressed concern that the situation could now spiral out of control.

The attack marks a notable escalation in an already tense Lebanese political climate after weeks of demonstrations and riots orchestrated by Hezbollah, the pro-Syrian Shia Islamist group, designed to bring down the western-backed Government. Last month, clashes between Hezbollah and pro-government supporters led to the deaths of nine people.

Initial reports put the death toll much higher at 12, but this was later revised to three by police officials, who nonetheless warned that the figure could rise.

No-one has so far taken responsibility for the incident, which police said targeted commuters on their way to work in the capital. Television footage of the scene showed a minibus with its roof torn off and destroyed vehicles, one of which was surrounded by a pool of blood.

The location of the blast is also believed to be significant as Bikfaya is the ancestral home of the Gemayels, one of Lebanon's most prominent Christian families. Pierre Gemayel, who was the Government's Industry Minister, was assassinated last November, triggering a massive protest of defiance against Syria and Hezbollah.

Mr Gemayel's assassination was the latest in a string of attempted political killings which have taken place since the murder of Hariri on February 14 2005 – an occurrence which set off a wave of unrest that forced Syria to end its 29-year military grip on its tiny neighbour.

The US accuses Syria of masterminding the killing and the subsequent attacks, a charge which Damascus has denied. The United Nations is investigating the killing, but has failed to finish its inquiry.

Nicholas Blanford, correspondent for The Times in Beirut, said that the nature of today’s attack was unusual in Lebanon. He said: “We have had drive-by shootings of politicians and random bomb attacks which have been designed to scare people rather than hurt them, but today’s attack was clearly intended to cause casualties.”

He said that government sources believed the purpose of the attack was two-fold - firstly serving as a warning to pro-government supporters planning a mass rally in the capital tomorrow to mark the death of Hariri.

“It is aimed at scaring off Christians from coming down to Beirut for tomorrow’s rally - after all, many of them would be making their way in buses just like those that were bombed,” said Blanford. He added that the other message appeared to be aimed at Amin Gemayel, president of the country in the 1980s and father of Pierre, the assassinated minister.

“The town in which the bombing took place is the family seat of the Gemayel clan,” he said. “Amin Gemayel has just been to the US to meet with President Bush and my sources say the attack marks a sign of displeasure about the visit.”

But Hariri’s son, Saad, leader of the majority anti-Syrian coalition, said that tomorrow’s memorial would go ahead as planned. He added that today’s events displayed the need for the UN-backed tribunal to try suspects in his father’s killing – a prospect presently curtailed by Hezbollah which is holding back from endorsing the tribunal, saying it could be used as a political tool.

Today's bombings were the first since Pierre Gemayel’s murder, and analysts said there had been signs a deal was in the pipeline to end the political crisis.

“Every time the possibility of practical solutions looms on the horizon between the Lebanese factions to strengthen their unity, the enemies of Lebanon rush to commit a new crime against innocents,” said Emile Lahoud, the pro-Syrian President, in response to the attack.

Mrs Beckett condemned the attack, adding: “I take this opportunity to reiterate Britain’s support for all those in Lebanon working to promote national unity and making efforts to overcome the current political impasse through peaceful dialogue.”

Jacques Chirac, French President, described today’s events “revolting”, saying the bombers intended to “plunge all of Lebanon back into violence.” His words were echoed by the German government, currently presiding over the EU, which issued a statement urging “all sides in Lebanon to take a determined stand against violence and to do everything they can to prevent the situation from escalating.”

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