Eleven Lebanese government ministers, 10 of them from Hezbollah and its allies, announced their resignation on Wednesday, calling on President Michel Suleiman to form a new government.

A United Nations-backed tribunal investigating the 2005 assassination of former Lebanese prime minister Rafik Hariri, the father of current Lebanese PM Saad Hariri, is widely expected to name members of the Hezbollah in upcoming indictments, which many fear could re-ignite hostilities between Lebanon's rival Shiite and Sunni Muslims.

Open gallery view Hezbollah leader Hassan Nasrallah Credit: AP

A Hezbollah minister had told Hezbollah's Al-Manar TV that Hezbollah ministers were planning to resign Wednesday afternoon unless Saad Hariri agreed to their demand to convene an urgent Cabinet meeting over the tribunal crisis.

Ten ministers from Hezbollah and its political allies carried through on that threat on Wednesday afternoon and were later joined by an eleventh minister, Adnan Sayyed Hussein, effectively collapsing Saad Hariri's government.

"Clearing the way for the formation of a new government ... the ministers present their resignation, hoping that the president will quickly take the required steps for forming a new government," said Gebran Bassil, a Christian government minister speaking for Hezbollah and its allies.

Hariri, whose coalition has been sharing power with the Iranian-backed militant group, met with U.S. President Barack Obama in Washington on Wednesday. After the meeting, Hariri cut short the remainder of his U.S. trip to deal with the crisis.

Hariri made no public comment after meeting Obama, but the official said Obama offered U.S. support. The official discussed the matter on condition of anonymity due to security and diplomatic concerns.

Hezbollah and its allies had 10 ministers in Lebanon's 30-member Cabinet.

Stalemate over the tribunal had crippled Hariri's 14-month-old "unity" government. The cabinet met, briefly, just once in the last two months and the government could not

secure parliamentary approval for the 2010 budget.

Violence has been a major concern as tensions rise in Lebanon, where Shiites, Sunnis and Christians each make up about a third of the country's four million people. In 2008, sectarian clashes killed 81 people and nearly plunged Lebanon into another civil war.

Rafik Hariri's assassination in a 2005 bombing that killed 22 other people both stunned and polarized Lebanon. He was a Sunni who was a hero to his own community and backed by many Christians who sympathized with his efforts in the last few months of his life to reduce Syrian influence in the country. A string of assassinations of anti-Syrian politicians and public figures followed, which UN investigators have said may have been connected to the Hariri killing.

Hezbollah denied any role in the Hariri assassination and denounced the UN tribunal as a conspiracy against it.

On Tuesday, officials announced that a diplomatic push by Syria and Saudi Arabia had failed to reach a deal to ease political tensions in Lebanon.