Lebanese President Michel Suleiman accepted the resignation of Prime Minister Najib Mikati on Saturday, local media said, paving the way for a caretaker government after a political standoff with the powerful Hezbollah movement.
Mikati's resignation could plunge Lebanon, already struggling to cope with a spillover of violence and refugees from neighbouring Syria's civil war, into further turmoil and uncertainty three months ahead of a planned parliamentary election.
The resignation on Friday came after a two-day ministerial meeting remained deadlocked by a dispute with the Shi'ite group Hezbollah, a militant and political movement that has dominated Lebanese politics in recent years.
"I did not inform anyone of my decision in order to avoid any pressure from any side," he was quoted as telling President Suleiman by the local news website Naharnet.
"My decision was a personal one ... It is now important that dialogue among the Lebanese begin. I hope that the resignation will pave the way for a solution to the political deadlock in the country."
Hezbollah opposed extending the term of a senior security official and the creation of an oversight body for the planned June parliamentary elections, which may now be delayed over the collapse of Mikati's government.
Major General Ashraf Rifi, head of Lebanon's internal security forces, is due to retire early next month. Rifi, like Mikati, is a Sunni Muslim from Tripoli, and is distrusted by Hezbollah.
Mikati became prime minister in 2011 after Hezbollah and its partners brought down the unity government of Saad al-Hariri. But tensions over Syria have put him at odds with the group that brought him to power and which strongly backs President Bashar al-Assad's battle against rebels and protesters in Syria.
Mikati backed a policy of "dissociation" from the conflict, hoping to keep Lebanon from being dragged in to the two-year civil war in its larger neighbour.
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 Mikati to step down, said his resignation "opens the possibility of fresh dialogue" between Lebanon's political camps.
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 clashes on Friday between militants supporting opposing sides of the Syria conflict.
Sporadic clashes erupted for a third day in Tripoli on Saturday morning, residents said, with two wounded by sniper fire.
A tide of Syrian refugees pouring into the country, as well as Lebanon's own political turmoil have caused a sharp slowdown in Lebanon's economy and a 67 percent surge in its budget deficit last year.