Beirut, Jan 13 (Agencies): The collapse of Lebanon's government plunged the country into deep political uncertainty today after a year of relative stability, as the president began the process of putting a new administration together.

President Michel Suleiman asked Saad Hariri to stay on as caretaker prime minister after the Iranian-backed militant group Hezbollah and its allies resigned on Wednesday and brought
down Hariri's government.

The crisis was the climax of tensions that have been simmering for months over the UN tribunal investigating the 2005 assassination of Hariri's father, former Prime Minister Rafik Hariri. The tribunal is widely expected to indict members of Hezbollah soon, which many fear could rekindle violence in the tiny nation plagued for decades by war and civil strife.

Lebanon's 14-month-old unity government was an uneasy coalition linking bitter rivals - a Western-backed bloc led by Hariri and the Shiite Hezbollah - that was an attempt to stabilise the country. But in reality, it had been paralysed for months because of disputes over the Hariri tribunal.

Hezbollah, which is supported by Syria and Iran and maintains an arsenal that far outweighs that of the national army, denounces the Netherlands-based tribunal as a conspiracy by the US and Israel. It had been pressuring Hariri to reject any of its findings even before they came out, but Hariri has refused to break cooperation with the tribunal.

Now, the chasm between the two sides is deepening with Hezbollah accusing Hariri's bloc of bowing to the West.

Hezbollah's ministers timed their resignations to coincide with Hariri's meeting with President Barack Obama in Washington, forcing him to meet the American president as a caretaker Prime Minister.