The appointment of Najib Mikati, backed by Hizbullah, to Lebanon's premiership provoked Sunni anger this week, Lucy Fielder reports from Beirut Sunni-Shia tensions in Lebanon soared again this week as Hizbullah's alliance secured the majority needed to block Saad Al-Hariri from the premiership and to see its choice, billionaire tycoon Najib Mikati, charged with forming the next government. Tripoli, Mikati's constituency but also Al-Hariri's stronghold, witnessed the biggest protests, but the "day of rage" called for by some of the former prime minister's allies spread also to the western Bekaa Valley, Sidon in the south and the capital Beirut. Demonstrations took a strongly sectarian tone and some turned violent, with minor clashes with the army, roads blocked by burning tyres and the torching of a vehicle used by Al-Jazeera journalists. Under Lebanon's sectarian political system, the prime minister must be a Sunni. Many in the community see Hizbullah's mustering of a majority of MPs as the Shia community, represented by the group, taking over "their" political post. That's extremely sensitive in Lebanon, whose 1975-1990 civil war was largely waged over the distribution of power between its main sects. Mikati is seen as a moderate who would under other circumstances have been a strong candidate. He was part of the parliamentary majority Al-Hariri won in 2009 and hitherto had good relations with him, while maintaining close links with Syria. The telecoms magnate also has a strong constituency in Tripoli. He was briefly caretaker prime minister following the assassination of Rafik Al-Hariri in 2005. But simply by accepting the premiership, and by implication Hizbullah's demands to withdraw Lebanon's official support for the Special Tribunal for Lebanon, he appears to be on a collision course with Al-Hariri and his supporters. Mikati extended a hand to his rivals in his acceptance speech at the presidential Baabda Palace on Tuesday. But Al-Hariri has so far made clear he would not take part in any government that his team sees as "appointed" by Hizbullah. Amal Saad Ghorayeb, an expert on Hizbullah and the Beirut-based research advisor for the Doha Institute, said the Sunni pressure seemed calculated to encourage Mikati to back down. "Al-Hariri's trying to get political capital out of this but he won't be able to use it," she said. "I think in the end the Al-Hariri camp is going to have to back down and diffuse tensions in the next couple of days." Lebanon's Mustaqbal (Future) newspaper, the mouthpiece of Al-Hariri's movement of the same name, echoed the rhetoric of many members of the 14 March movement by calling Hizbullah's manoeuvre "a coup and a seizure of power that serves Damascus and Tehran", two regional powers that back Hizbullah. "The designation of Prime Minister Najib Mikati to head the government is not enough. What is important is the governmental formation, while the question is: Can and will Mikati agree to form a one-colour government?" the paper asked. Hizbullah and its allies brought down Al-Hariri's government in mid-January, after months of Syrian-Saudi negotiations to end Lebanon's impasse over the Special Tribunal for Lebanon were announced a failure. The Shia military and political group alleged US interference, and its ministers and their allies -- 11 in total -- resigned just as Al-Hariri met US President Barack Obama in Washington. The United States has been a hawkish supporter of the tribunal, which is to try suspects in the Al-Hariri assassination. Those indictments, which were filed secretly in mid-January, are widely expected to name Hizbullah members. The guerrilla group denies any role in the killing and sees the court as a US-Israeli plot against it. It wanted Al-Hariri to sever Lebanon's official support for the tribunal, withdraw its judges, end its funding, cancel the protocol and openly reject in advance any indictment touching Hizbullah. "Hizbullah sees this as a declaration of war, and its stand is going to be hardline," Saad-Ghorayeb said. "We've seen from the past how far it will go." Al-Hariri and his US backers have wagered incorrectly that the spectre of Sunni-Shia strife would stop Hizbullah from infringing on Sunni sensibilities, Saad-Ghorayeb said. "Hizbullah has shown it will no longer be intimidated by the Sunni-Shia scarecrow," she said. "When Al-Hariri and the United States cross its red lines, the gloves are off." Highly damaging though the perception is that Hizbullah has "seized" the Sunni seat of power, the MPs who switched from Al-Hariri's camp to Hizbullah's appear to have decided the alternative was worse. Hizbullah had made clear it would escalate, likely beginning with demonstrations, if Al-Hariri had kept his post without conceding to the group's demands on the tribunal. "I see this as the lesser of two evils," Saad-Ghorayeb said. "The Al-Hariri option could have spelt civil or even regional war." Many newspaper reports in recent weeks have said Al-Hariri was ready to cut a deal in return for a strengthened mandate and a free hand on the economy. But the prospect of a deal allowing Hizbullah breathing space appears to have alarmed the United States. The resignations by Hizbullah's alliance were enough to bring down Al-Hariri's cabinet and necessitate consultations with President Michel Suleiman. On Monday and Tuesday, political blocs visited him to name their choices, but the shape of the winning side emerged before the weekend, with a typically spectacular announcement by mercurial Druze leader Walid Jumblatt of his support for the position held by Hizbullah and its ally Syria. At the time, the candidate in question appeared to be Omar Karami, but once Mikati was onboard, with his four allied MPs, it appeared likely Al-Hariri's premiership was over for now at least. Karami was seen as a wholly pro-Syrian candidate, rather than a centrist like Mikati. Saad-Ghorayeb said Jumblatt's calculations were based on the likelihood of serious strife -- beyond even the May 2008 strife -- if the indictments did accuse Hizbullah. "This time would be different and Jumblatt wants to make sure he and his areas can stay out of it; that's why he's being cautious," she said. The fighting in May 2008, Lebanon's last serious bout of instability, was prompted by a government crackdown on Hizbullah's communications networks. This time, Saad-Ghorayeb pointed out, Hizbullah sees the indictments as a decision to go after its fighters, which could be even more explosive. By Lucy Fielder