Updated

Lebanon's Western-backed coalition called on supporters Wednesday to hold daily sit-ins in downtown Beirut to protest the growing power of the Iran-backed militant group Hezbollah.

The Shiite group and its allies toppled Lebanon's government two weeks ago and secured enough support in parliament to name their own pick for prime minister Tuesday. Opponents of Hezbollah say having an Iranian proxy at the helm of Lebanon's government would be disastrous and lead to international isolation.

Fares Soeid, a senior official with the Western-backed coalition known as March 14, said the country is becoming entirely beholden to Hezbollah. He called on Lebanese to gather peacefully every evening, holding Lebanese flags, at Martyrs Square in downtown Beirut.

Wary of Hezbollah's position, thousands of Sunnis poured into the streets across Lebanon over the past two days, burning tires, throwing rocks and accusing the militant group of a coup d'etat.

Some of the most intense protests Tuesday took place in the northern city of Tripoli, a hotbed of Sunni fundamentalism. On Wednesday, traffic had returned to normal and schools and shops had opened. Two armored personnel carriers and several soldiers stood guard nearby.

As the situation calmed, Prime Minister-designate Najib Mikati began the process of forming a new Cabinet on Wednesday by visiting former prime ministers — a move dictated by protocol — including outgoing Premier Saad Hariri. Neither man spoke to the media after the 15-minute meeting.

Mikati, a billionaire businessman and Harvard graduate, has called for a unity government that would bring together Lebanon's diverse society — a sign that the militant group does not want to push its growing power too far and risk isolation abroad and an escalation of sectarian tensions at home.

But the fact that Hezbollah, a group known as much for its ties to Shiite Iran as for its hostility to Israel, chose Mikati and secured enough backing in parliament to make him prime minister underscores Tehran's growing influence in the region at a time when Washington's is waning.

Hariri has insisted he will not join a government led by a Hezbollah pick.

Saudi Arabia's Foreign Ministry advised its citizens on Wednesday to avoid traveling to Lebanon "until calm and stability return." Saudi Arabia, the Sunni power in the region, is a strong backer of Hariri, who also holds Saudi citizenship.

Hariri's Future Movement placed banners in Tripoli that accused Mikati of being given a "religious assignment" by Iran's Supreme Leader Ayatollah Ali Khamenei — the spiritual leader for many Hezbollah members, including the group's chief Sheik Hassan Nasrallah.

In Washington, Secretary of State Hillary Rodham Clinton warned that formation of a government dominated by Hezbollah would mean changes in U.S. relations with Lebanon.

Lebanon's political crisis has its origins in the assassination of Hariri's father, former prime minister Rafik Hariri, who was killed in a massive truck bombing on Feb. 14, 2005 along with 22 others.

A U.N.-backed tribunal is widely expected to accuse Hezbollah in the crime in a sealed indictment that was issued Jan. 17. Hezbollah has denied any link to the killing and accused the Netherlands-based tribunal of trying to frame its members at the behest of Israel and the United States.

Ministers from Hezbollah and its allies walked out of Saad Hariri's government, forcing it to collapse, after Hariri refused to renounce the court investigating his father's murder.