(AP) — The leader of Lebanon’s Shiite militant group Hezbollah appealed for calm Tuesday after people blocked roads and burned tires in Beirut to protest the kidnapping of 11 Lebanese Shiites in neighboring Syria.

The abductions in Syria’s northern Aleppo province threatened to ignite dangerous sectarian tensions and fueled fears that Lebanon is getting drawn into the chaos next door.

The Lebanese were on their way home from a religious pilgrimage in Iran when Syrian rebels intercepted their vehicles, Syria’s state-run SANA news agency said. The rebels abducted the 11 men and a Syrian driver. The women were released.

Lebanese security officials confirmed the kidnapping.

As the news of the kidnappings spread, residents of the southern suburbs of Beirut, a Shiite area, took to the streets and burned tires and blocked roads in protest. The leader of Hezbollah, a strong ally of the Syrian regime, appealed for calm and warned his followers against revenge attacks targeting Syrians.

“This is strictly prohibited,” Sheik Hassan Nasrallah said in a televised speech.

He said the Lebanese government must press for the pilgrims’ release.

“We will work day and night until these beloved people are with us,” Nasrallah said.

Hezbollah has stood by Syrian President Bashar Assad as he struggles to put down a 15-month-old uprising.

Sunnis form the backbone of the Syrian revolt, which has unleashed boiling sectarian tensions. Assad and the ruling elite in Syria belong to the tiny Alawite sect, an offshoot of Shiism.

Within hours of the kidnappings, the Syrian government began moving into Azaz in Aleppo province, where the abductions took place, activists said.

Syria’s uprising began in March 2011 with mostly peaceful calls for reform, but the government’s brutal crackdown on dissent led many in the opposition to take up arms. The U.N. estimates more than 9,000 people have been killed as the conflict spirals toward civil war.

Tuesday’s kidnappings come at a time of deep tension in Lebanon over Syria. The countries share a complex web of political and sectarian ties and rivalries, which can quickly turn violent. The conflict already has spilled across the border, with deadly results.

Lebanese Sunni groups supporting and opposing the Damascus regime fired rocket-propelled grenades and machine guns in Beirut early Monday, killing at least two people. It was among the most serious fighting in the capital since 2008.

The spark for the violence was the killing Sunday of Sheik Ahmed Abdul-Wahid, an anti-Syrian Sunni cleric, and his bodyguard in northern Lebanon. A Lebanese soldier shot the men, apparently after they failed to stop at an army checkpoint. The killing fueled deep anger over the perceived support of some of Lebanon’s security forces for the Syrian regime.

Syria had troops on the ground in Lebanon for nearly 30 years until 2005 and still has strong ties to Lebanon’s security services.

Earlier this month, the arrest of Shadi Mawlawi, an outspoken Lebanese critic of Assad, set off several days of clashes in northern Lebanon that killed eight people. Mawlawi was accused of belonging to a terrorist group.

On Tuesday, authorities released him from jail on $330 bail, a move many hoped would defuse tensions. During a news conference in the northern Lebanese city of Tripoli, Mawlawi said he was “subjected to psychological pressure and torture” following his May 12 arrest and was forced to give false confessions that he was connected to terror groups.

Mawlawi denies any links to such groups.

As he spoke, supporters at the news conference lashed out at the Syrian regime, saying, “Assad is the enemy of God.”