Lebanon's Prime Minister Najib Mikati announced his government's resignation on Friday after a cabinet dispute with Shi'ite group Hezbollah over preparations for a parliamentary election and extending the term of a senior security official.
Mr Mikati's announcement after a deadlocked ministerial meeting plunged Lebanon, already struggling to cope with a spillover of bloodshed and refugees from neighbouring Syria, into fresh uncertainty three months before the planned election.
He called for a unity government to be set up to save the country from "regional fires and ... internal divisions".
"I announce the resignation of the government, perhaps as the only way for Lebanon's main political blocs to assume their responsibilities, and come together to pull Lebanon out of an unknown tunnel," Mr Mikati said.
Mr Mikati resigned just two hours after a cabinet meeting in which Shi'ite group Hezbollah and its allies blocked the creation of a supervisory body for the parliamentary vote and opposed extending the term of a senior security official.
Major General Ashraf Rifi, head of Lebanon's internal security forces, is due to retire early next month. Mr Rifi, like Mr Mikati, is a Sunni Muslim from Tripoli, and is distrusted by Hezbollah.
Mr Mikati became premier in 2011 after Hezbollah and its partners brought down the unity government of Saad al-Hariri. Tensions over Syria have put him at odds with the militant group which brought him to power and which strongly backs president Bashar al-Assad's battle against rebels and protesters.
Election delay
Lebanon's rival politicians have yet to agree arrangements for the parliamentary poll, due in June, and the collapse of the government could delay it further.
"It appears that the new election law will not be agreed within a time frame which allow parliamentary elections to be held on schedule,"Mr Mikati said.
Under Lebanon's confessional division of power, the prime minister must be a Sunni Muslim, the president a Maronite Christian and the speaker of parliament a Shi'ite Muslim.
Former prime minister Fouad Siniora, a close political ally of Hariri who has frequently called for Mr Mikati to step down, said his resignation "opens the possibility of fresh dialogue" between Lebanon's political camps.
Mr Mikati has sought to distance his country - which fought its own 15-year civil war - from Syria's strife. But in the ex-prime minister's home city of Tripoli, two people died in clashestoday between militants supporting opposing sides of the Syria conflict.
Clashes erupted again this evening, residents said, and supporters of Mr Mikati and Mr Rifi blocked roads around Tripoli's main square.
A tide of Syrian refugees pouring into Lebanon and the country's own domestic turmoil have caused a sharp slowdown in Lebanon's economy and a 67 pe cent surge in its budget deficit last year.