TRIPOLI, Lebanon (AP) -- In scenes reminiscent of Lebanon's devastating civil war, charred bodies lay in the streets Friday after twin car bombs exploded outside mosques packed with worshippers, killing 29 people and wounding hundreds.
The coordinated attacks in this predominantly Sunni city -- the deadliest fallout from Syria's civil war to hit Lebanon -- raised sectarian tensions to dangerous levels amid fears the country was slipping into a prolonged cycle of revenge.
The blasts marked the second such attack in just over a week. A deadly car bombing targeted an overwhelmingly Shiite district south of Beirut controlled by the militant Hezbollah group on Aug. 15, demonstrating the alarming degree to which the country is being torn apart by the civil war next door.
Friday's attacks shocked residents of Tripoli, which has been the scene of frequent clashes between supporters and opponents of President Bashar Assad in recent months. But the city, Lebanon's second-largest, has not seen such bombings in decades.
The blasts were clearly intended to cause maximum civilian casualties, timed to go off at midday Friday outside the Taqwa and Salam mosques, which are known to be filled with worshippers at that time on the Muslim day of prayer.
"Lebanon has officially entered the regional war which has been raging in Syria and Iraq," said Randa Slim, a scholar at the Washington-based Middle East Institute.
"There are serious fears that the country has entered a vicious cycle of tit-for-tat explosions and car bombs. A dynamic of violence and reprisals, once set in, is hard to reverse," she said.
Local TV stations aired shocking footage of the first moments following the explosions: Bodies scattered beside burning cars, charred victims trapped in smoking vehicles and bloodied casualties emerging from thick, black smoke being ferried away by screaming residents.
In one video, apparently recorded by a closed-circuit television camera in the area, scores of terrified worshippers were seen spilling out of one of the mosques in a crushing stampede immediately after the explosion struck.
In the chaotic aftermath, bearded gunmen took to the streets of Tripoli, firing in the air, attacking soldiers and sealing off the two mosques where the car bombs went off. Later, they roamed the streets in SUVs, weapons sticking out of the windows.
The two explosions went off about five minutes apart. The force of the blast at the Taqwa mosque propelled a car onto its roof.
President Michel Suleiman cut short a visit abroad and returned to the country to follow the situation. He described the attacks as a "massacre" aimed at sowing strife among Lebanese.
Hezbollah was quick to condemn the bombings and in a strongly worded statement, expressed "utmost solidarity" with the people of Tripoli.
However, residents of the city -- long known as a hotbed for Sunni fundamentalists -- were quick to point fingers at the Syria-backed group, blaming it for bringing destruction to Lebanon because of its open involvement in the Syrian civil war. In an ominous sign, a prominent Salafist sheikh, Dai al-Islam Shahhal, said Sunnis in Tripoli would take security in their own hands, raising the specter of armed vigilantes.
"Hassan Nasrallah was behind this," a man shouted hysterically at the scene, blaming the Hezbollah leader.
The grand mufti, Lebanon's top Sunni cleric, urged calm and unity in a televised address, but there was little of that to be seen in Tripoli Friday.
The open participation of the group on behalf of the embattled Assad regime has sent sectarian tensions soaring in Lebanon, a deeply divided country that never fully recovered from its own devastating civil war, which ended in 1990.
During that conflict, which pitted Christians against Muslims, tit-for-tat car bombings were common and contributed to the estimated 150,000 people killed during the 15-year conflict. Since the end of the war, there have been numerous car bombings targeting politicians and journalists, but attacks intended to cause civilian casualties have been rare.
The Syrian civil war, and Hezbollah's military involvement in support of Assad's forces, has rekindled the polarization along sectarian lines and street clashes have erupted on numerous occasions.
Attacks have become common in the past few months against Shiite strongholds in Lebanon, in what many see as retaliation by extremist groups for Hezbollah's role in Syria. The Aug. 15 car bombing in a Shiite stronghold of Hezbollah in the southern suburbs of Beirut killed 27 people and wounded more than 300. A less powerful car bomb targeted the same area on July 9, wounding more than 50.