BEIRUT: Gunmen from rival Sunni and Shiite Muslim villages in northern Syria have freed more than 200 people snatched in tit-for-tat kidnappings this month, easing tensions that threatened to touch off more sectarian violence, activists said Friday.

In Syria's largest city of Aleppo, three explosions that appeared to be caused by missiles killed at least 14 people, activists said, adding that dozens of others were feared to be trapped under the rubble of damaged buildings.

The wave of abductions in a rural part of Idlib province highlighted how much the civil war between the regime of President Bashar Assad and the hundreds of rebel groups seeking his ouster has enflamed tensions between Syria's myriad religious groups.

The Syrian regime, established more than four decades ago by Assad's father, Hafez, has largely stocked the upper ranks of the country's security agencies and armed forces with members of the ruling family's minority Alawite sect, an offshoot of Shiite Islam. Most of the rebels fighting Assad's forces are poor, rural members of Syria's Sunni majority.

Other religious minority communities, like Christians and Druze, have largely remained on the sidelines.

As the conflict approaches its third year, its sectarian divide is worsening. This month, clashes broke out between Sunni and Shiite villages in the area of Qusair, near the Lebanese border. Islamic extremists who have joined the rebels have destroyed Christian liquor stores, and sometimes refer to their dead adversaries with derogatory names insulting their sects.

The Idlib kidnappings showed how quickly sectarian tensions can escalate, but also that local communities are still capable of pulling back from the brink.

Opposition activists say the abductions began Feb. 14 when a bus carrying dozens of Shiite civilians, mostly women and children, disappeared on the road to Damascus. Gunmen from the area's two Shiite villages, Fua and Kifarya, responded by snatching civilians from the Sunni villages nearby.

Some of the Sunnis were nabbed at makeshift checkpoints on rural roads, while others were taken while entering the provincial capital, which government troops still control. Many of the Sunnis captives, too, were woman and children.

"They started taking over buses from the opposition villages that were heading to Idlib city," said activist Hamza Abu al-Hassan from the village of Binnish. "Some of them had government jobs or had to file papers or were just going to visit their families."

The total number of those kidnapped remains unclear. Abu al-Hassan said they included about 35 Shiites and more than 250 Sunnis. Other activists gave higher figures.

It also remains unclear who hijacked the bus carrying the Shiite civilians. Local activists said no rebels claimed responsibility, possibly because the kidnappers were criminals seeking ransom or because the move was immediately criticized by opposition groups.

Local rebels threatened to storm the Shiite villages, whose residents they say have been armed by the government. But the crisis was resolved early Thursday when the Shiite captives returned home, followed by the release of the Sunni captives later in the day, activists said.

Residents of the Shiite villages could not be reached for comment, though a Facebook page for the larger of the villages, Fua, said in a post Thursday that the captives had returned.

"With God's help we have liberated our kidnapped sisters from hands of the enemies of God," the post said. It also called for "retribution."

Although the abductees have all been freed, the fundamental divide between the Sunni and Shiite villages remains.

"There will have to be a battle in the future because the army is there," Ismael Khatib, a rebel from the village of Taftanaz, said via Skype. "They have tanks there that shell us, so it is natural that the rebels will liberate the area to stop the shelling."

The explosions Friday in Aleppo, Syria's largest city and commercial capital, hit the eastern neighborhoods of Ard al-Hamra and Tariq al-Bab, the Britain-based Syrian

Observatory for Human Rights said.

The Observatory said at least 14 people were killed, while the Aleppo Media Center activist group put the death toll at 16.

Videos posted online showed what appeared to be the aftermath of the explosions.

In one video that the caption said was from Ard al-Hamra, dozens of people, many of them with flashlights, scour the rubble in the dark in search of survivors. In another clip, at least nine bodies are laid out on a floor, some of them wrapped in blankets.

The videos appeared authentic and corresponded to other AP reporting.

In Cairo, the Syrian National Coalition, an opposition umbrella group, said it would welcome U.S. and Russian mediation to negotiate a peace deal to end the country's civil wall but insisted it would not allow Assad or members of his security services to participate in the talks. The announcement came in a statement posted on the coalition's Facebook page following two days of meetings in Cairo meant to firm up the group's position on whether to engage in talks.

"Bashar Assad and the security and military leadership responsible for the state of Syria today must step down and be considered outside this political process," the statement said. "They cannot be part of any political solution for Syria and must be held accountable for their crimes."

Coalition chief Mouaz al-Khatib has angered some in the opposition by offering to sit down with regime figures to help end the civil war. Friday's announcement appeared aimed at setting the boundaries for any future talks by stressing that Assad and his aides cannot be part of any negotiations.

The Coalition also agreed to form a transitional government in rebel-held areas and said it will meet on March 2 in Turkey to choose a leader for the administration, spokesman Walid al-Bunni told reporters in Cairo.

The opposition umbrella group has been struggling to agree on the leadership of a provisional administration since the Coalition was formed late last year. The group has met on previous occasions to agree on an interim prime minister, but failed to reach a compromise.

Also Friday, Reporters Without Borders said French freelance photographer Olivier Voisin was seriously wounded a day earlier in Idlib province.

The media watchdog said Voisin sustained shrapnel wounds to his head and arm, and underwent surgery at a hospital in Antakya, Turkey.

Hospital officials in Turkey confirmed that Voisin was in the country for treatment. The officials spoke on condition of anonymity because they were not authorized to brief the media.

The New York-based Human Rights Watch urged the U.N. on Friday to require Syrian authorities to grant international monitors access to its detention facilities, following the death of a peace activist in custody.

Omar Aziz, 64, died on Feb. 16 of health complications at a military hospital, the group said in a statement. It also described how a newly released detainee also reported witnessing the death of Ayham Ghazzoul, an imprisoned 26-year-old rights activist. Both had been detained by security forces in November.

Human rights groups and the opposition accuse Syrian authorities of holding tens of thousands of prisoners, many of whom it is feared have been tortured.