BEIRUT: Fighting intensified in northern Lebanon on Saturday as outgoing Prime Minister Najib Mikati called for a “salvation” caretaker government to take over, a day after he resigned due to a political standoff with the Hezbollah movement.

Local media reported that President Michel Suleiman had accepted Mikati's resignation, which could plunge Lebanon into further turmoil and uncertainty three months before a planned parliamentary election.

The politically volatile country is struggling to cope with a spillover of violence and a wave of refugees from the two-year-old civil war in Syria, the country's larger neighbour which has close ties to the Iranian-backed Hezbollah.

Mikati's resignation has sparked fresh clashes in Lebanon's northern port city of Tripoli, where residents said fighting intensified on Saturday evening to include heavy weaponry such as mortar bombs.

Lebanese forces trying to clamp down on the unrest began returning fire in the districts where fighting had broken out, residents said, but were unable to halt the violence.

Tripoli is home to a Sunni Muslim majority largely supportive of Syria's Sunni-led uprising, and they have sporadically clashed with a small enclave of pro-Hezbollah minority Alawites - the same sect to which Syrian President Bashar al-Assad belongs.

The tensions have increased over the resignation of Mikati, a Sunni. Supporters of Mikati burnt tyres and blocked roads in Tripoli on Friday when he announced he would step down.

Security sources said one man in Tripoli's Alawite neighbourhood was killed by sniper fire on Saturday afternoon.

No updated toll was available after clashes flared in the evening.

Deadlocked Government

Mikati's resignation on Friday came after a ministerial meeting was deadlocked by a dispute with Hezbollah.

The Shia militant and political movement has dominated Lebanese politics in recent years and helped put Mikati into office after toppling the previous government.

“Now it is important for dialogue to begin and for a salvation government to be established during this difficult period,” Mikati wrote on his official Twitter page after handing in his resignation to the president. “I thank God that I left office the same way I came in, with integrity.”

Hezbollah opposed extending the term of a senior security official, Major General Ashraf Rifi, and the creation of an oversight body for the planned June election, which may now be delayed after the collapse of Mikati's government.

Rifi, head of Lebanon's internal security forces, is due to retire early next month. He, like Mikati, is a Sunni Muslim from Tripoli, and is distrusted by Hezbollah.

Putting together a caretaker government could take months.

It took Mikati five months to construct his government after he became prime minister in 2011 when 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 Assad in the Syrian civil war.

Under Lebanon's division of power, the prime minister must be a Sunni Muslim, the president a Maronite Christian and the speaker of parliament a Shia Muslim.

Former Prime Minister Fouad Siniora, a close political ally of Hariri who had frequently called for Mikati to step down, said the resignation “opens the possibility of fresh dialogue” between Lebanon's political camps.

Mikati had sought to distance his country - which fought its own 15-year-long civil war - from Syria's strife.

The influx of Syrian refugees, as well as Lebanon's own political divisions, have caused a sharp slowdown in Lebanon's economy and a 67 percent surge in its budget deficit last year.

United Nations Secretary General Ban Ki-moon called for calm in a statement after Mikati's resignation.

“At this challenging time for the region, the secretary-general calls on all parties Lebanon to remain united behind the leadership of President Suleiman,” the statement said.

“He also calls on them to work together with the institutions of the state to maintain calm and stability, to respect Lebanon's policy of disassociation (in Syria) ... and to support the role of the Lebanese Armed Forces in sustaining national unity, sovereignty and security.”