Tension increased in Lebanon on Monday after after Sunni lawmakers called for a "day of rage" throughout the country on Tuesday to protest against gains by Iranian-backed Hezbollah.
The Shiite militant group secured the support from a majority of parliament on Monday to nominate its candidate for prime minister, putting the Iranian-backed militant group in position to control Lebanon's new government.
Billionaire businessman Najib Mikati, a moderate politician and former premier, was set to clinch the nomination for prime minister after Shiite Hezbollah and its allies lined up the needed backing of at least 65 of the 128 parliament members,
Voting on the candidate began on Monday.
Hezbollah brought down the unity government with the Western-backed coalition earlier this month after Sunni Prime Minister Saad Hariri refused the group's demand to cease cooperation with a UN-backed tribunal investigating the 2005 assassination of his father, former Prime Minister Rafik Hariri.
The tribunal is widely expected to indict Hezbollah members in the assassination, something that has raised fears of renewed violence in the tiny, volatile country on Israel's northern border.
Hezbollah's opponents say a government led by the militant group would be disastrous for Lebanon and lead to international isolation.
The United States, which considers Hezbollah a terrorist organisation, has tried to move Lebanon firmly into a Western sphere.
A Hezbollah-led government would also raise tensions with Israel, which fought a 34-day war against Hezbollah in 2006 that left 1,200 Lebanese and 160 Israelis dead.
Several hundred Hariri supporters in the northern city of Tripoli, a predominantly Sunni area and a hotbed of fundamentalists, staged protests on Monday chanting slogans against Mikati, a lawmaker from Tripoli.
There were other protests in Beirut - tyres were set on fire and a road was blocked as protesters expressed their support for Hariri.
Mikati appealed for calm and, in a statement, called on Hariri supporters not to upset stability.
Hezbollah and its allies had the support of at least 57 seats and gained seven more from the bloc of Walid Jumblatt, the influential leader of the Druse sect.
With Mikati's vote, Hezbollah reached 65. The voting in parliament on a new candidate for prime minister was to continue on Tuesday.
Hezbollah leader Sheik Hassan Nasrallah said on Sunday if their candidate got the post of prime minister, the group will try to form another national unity government with Hariri's Western-backed bloc.
But Hariri said on Monday he would not join a government headed by a Hezbollah-backed candidate.
A statement issued by Hariri's office said there was no "consensual candidate" and made it clear that Hariri remained the Western-backed camp's choice for prime minister.