Three people are reported to have been killed and about 20 injured after bomb blasts tore through two buses near the Lebanese Christian mountain town of Bikfaya.
Television footage showed at least one bus totally destroyed and ambulances carrying away people on Tuesday.
Police sources had earlier put the death toll at about 12, but later reduced the figure.
Blood stains could seen at several places near the bus wreckage. One of the two buses was completely burnt out while the other was partially damaged, Al Jazeera's correspondent reported.
Hassan al-Sabaa, Lebanon's interior minister, said early investigations showed the bombs had exploded inside the minibuses.
The head of the Lebanese Red Cross said six of the wounded had been taken to a nearby hospital. "There could be more casualties," Georges Kettani said.
The buses were carrying people to work in Beirut from two Lebanese Christian towns.
The blasts wrecked the buses and other vehicles on a mountain road about 24km northeast of Beirut.
Tension has been running high in Lebanon since street clashes last month, between supporters and opponents of the Western-backed government, in which nine people were killed.
Pro-government groups had planned a mass memorial in Beirut's Martyrs Square on Wednesday to mark the assassination of Rafiq al-Hariri, the former prime minister, despite fears of friction with opposition supporters who have been camped out nearby since early December as part of a campaign to topple the anti-Syrian government.
The blasts took place amid signs that a deal to end the political crisis was close.
"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," Emile Lahoud, the Lebanese president, said.
Amin Gemayel, Lebanon's former president and a prominent Christian leader, told the the Voice of Lebanon radio station that "alien hands" were behind the explosions.
"Lebanese do not kill Lebanese," he said.
One of the buses was travelling from Bikfaya, the home town of Gemayel, whose son Pierre was assassinated in November.
Pierre Gemayel was the industry minister in the government of Fouad Siniora, the prime minister, which has been locked for months in a power struggle with the Hezbollah-led opposition.
Karim Pakradouni, a leader of Gemayel's Phalangist Party, said it was time for Lebanese to unite.
"The curse cast on Lebanon has not yet been lifted. Political messages in the world are relayed verbally or in writing. In Lebanon, they are written in blood," he said.
The attacks came a day before the second anniversary of the assassination of al-Hariri.
Walid Jumblatt, a senior leader of the governing March 14 movement, said: "[This attack] is to terrorise people who are coming to commemorate the anniversary of Rafiq al-Hariri's assassination.
"I don't have any physical evidence but they are delivering the message, practically on the ground."
Samir Franjieh, a parliamentarian, said: "This is a terrorist act of a new kind aimed at foiling the second anniversary of the assassination of martyr al-Hariri."
The bombings are the first since the killing of Pierre Gemayel, which was one of a string of actual or attempted political assassinations since al-Hariri's killing on February 14, 2005.
Many Lebanese have accused Syria of masterminding al-Hariri's killing and the subsequent attacks.
Damascus has denied any role. A UN inquiry has yet to complete its investigation.
Aljazeera+Agencies
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