Hariri's statement came as anger boiled over in Beirut after a video deemed offensive to the country’s Shia population was circulated online.
Lebanon's Saad Hariri said on Wednesday he is not a candidate for prime minister but insisted that formal consultations to designate a new premier will take place on Thursday as scheduled.
"I announce that I will not be a candidat e to form the coming government," Hariri said in a statement.
"I am heading tomorrow to take part in the consultations ... on this basis, insisting that they not be delayed for any reason," he said.
Hariri did not say who he would nominate for the post in the consultations which President Michel Aoun is due to host on Thursday. Aoun, a Maronite Christian, is required to designate the candidate with the most support among Lebanon's 128 MPs.
The only candidate with the support of Lebanon's Sunni Muslim religious establishment, Hariri had appeared the only candidate for the job earlier this week despite political tension with adversaries including Aoun.
But the picture was complicated when the Christian Lebanese Forces said it would name neither Hariri nor anyone else in the consultations, meaning his candidacy would not enjoy the support of either of Lebanon's two main Christian parties.
Mob moves through Tripoli
Hariri's announcement comes as a mob in Lebanon attacked the office of a Sunni Muslim religious leader in the northern city of Tripoli, smashing in windows early on Wednesday, reports said.
The assailants then moved to one of the city’s main squares and set fire to the municipality’s Christmas tree.
The violence indicated that the tensions that gripped the Lebanese capital, Beirut, a day earlier over an online video deemed offensive to the country’s Shia population are spreading to Tripoli, the country’s second-largest city. The state-run National News Agency reported that the military later detained four assailants in Tripoli but did not provide other details.
The military said a mob of men on motorcycles gathered outside the home of Sunni Mufti Sheik Malek al Shaar and rioted, “used profanity” and smashed property. The mob then moved to the square and threw firebombs at the Christmas tree, setting it on fire. The military said it arrested four men and confiscated their motorbikes.
On Tuesday, anger boiled over in Beirut after the offensive video was widely circulated online, showing a Sunni resident of Tripoli railing against the leaders of the country’s two main Shia groups, Hezbollah and Amal and religious Shia figures and using expletives. Their supporters descended on a protest camp in Beirut as security forces intervened to push them back, setting off hours of pitched street battles.
Angry assailants also attacked protest camps in the northern district Hermel and in the southern Sidon and Nabatiyeh on Tuesday.
The violence threatened to plunge Lebanon further into chaos and ignite sectarian strife amid two months of anti-government protests and a spiralling financial crisis.
The daily newspaper An Nahar said the assailants in Tripoli were angered because the Sunni mufti, al Shaar, had called the powerful Shia parliament speaker and head of Amal, Nabih Berri, to apologise for the video.
Supporters of the militant Hezbollah group and its close ally, the Amal movement, have been intolerant of the protesters’ criticism of their leaders and have tried for days, even before the video emerged, to attack the protest camps.
The anti-government protests, which erupted in mid-October, have spared no Lebanese politician, accusing the ruling elite of corruption and mismanagement, and calling for a government of independents. They have largely been peaceful, sparked by an intensifying economic crisis.
Berri, the parliament speaker, and outgoing Prime Minister Saad Hariri met on Tuesday and urged the Lebanese not to be "drawn toward strife", adding that some parties they didn’t name are working to incite violence in the country.