Lebanese Foreign Minister Adnan Mansur said Wednesday that a group of Lebanese Shiite Muslims kidnapped in Syria would be freed "within hours."
Lebanon's Hezbollah leader Hassan Nasrallah earlier urged restraint after Tuesday's kidnappings sparked protests by thousands of people here.
"According to information provided by an Arab country those kidnapped will be free within hours," Mansur told Al-Jadeed, a private satellite television station.
He identified the men behind the abductions as "a splinter group of the armed Syrian opposition," but did not give details.
The abductions of the pilgrims -- news reports put their number at between 11 and 13 -- were feared to further fuel sectarian tensions in Lebanon over the revolt in neighbouring Syria.
They were kidnapped as they headed home to Lebanon from a pilgrimage in Iran and the news prompted their families and thousands of supporters to pour out into the streets of Beirut's mainly Shiite southern suburbs to demand their release.
Protesters blocked several roads, including the old airport road, with burning tyres and garbage bins. The roads were reopened later in the evening.
Lebanon's state news agency said the rebel Free Syrian Army (FSA), which is seeking the overthrow of President Bashar al-Assad's regime, had abducted 13 pilgrims in northern Aleppo province.
Syrian media said an "armed terrorist gang" had kidnapped 11 Lebanese and their Syrian driver.
Nasrallah, a strong ally of the embattled regime in Damascus, appealed for calm and said his Shiite militant party was doing its utmost to ensure the safe release of the men.
"I call on everyone to show restraint," Nasrallah said in a televised speech. "It is not acceptable for anyone to block roads or carry out violent acts."
Nasrallah said contacts were underway with Syrian authorities and other countries in the region for a quick resolution.
"We will work day and night until those beloved are back with us," he vowed.
Nasrallah said Hezbollah was also in contact with Prime Minister Najib Mikati, whose government is dominated by the powerful militant group.
"The Lebanese state and government have a responsibility to work toward the release of those kidnapped," he said.
Nasrallah urged his followers not to carry out revenge attacks against Syrians in Lebanon.
Syrian state media said the kidnapping took place near the town of Aazaz, which sits along the border with Turkey. It said the men were part of a group of 53 pilgrims on board two buses.
The women were allowed to go free and returned to Beirut by plane early Wednesday.
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Among the pilgrims were 36 women, one of them said shortly after their arrival.
"After crossing the border between Turkey and Syria, we saw a white car pull up with men armed with Kalashnikovs inside," she said. "They told us they wanted to protect us from Syrian shelling. Then they handcuffed the men and lined them up against a wall."
Most women said the men presented themselves as belonging to the FSA.
"They terrorised us," said one of them.
Hezbollah MP Mohammad Raad, who was at the airport to welcome the women, said there were signs the matter would be settled "quickly."
Raad would not be drawn on whether rebels were behind the kidnapping when asked.
"We don't want to go into details of who is behind the abductions to make their release easier," he said. "We'll deal with that later."
Activists in Aleppo reached by AFP via Skype said Aazaz was undergoing fierce shelling Tuesday evening by regime forces who stormed the town.
The brother of one of those kidnapped said the FSA had vowed to release the men in exchange for rebels detained by Syrian authorities.
FSA spokesmen could not be reached for comment late Tuesday.
Mikati's office said he was making the necessary contacts to ensure the release of the men.
"Prime Minister Mikati has urged families of the kidnapped to remain calm and assured them he was following the issue closely to ensure the safety of those abducted and their quick release," a statement said.
The kidnapping took place amid heightened tension in Lebanon over the Syrian crisis.
Clashes between the pro- and anti-Assad camps in the country have left some 12 people dead in the past 10 days.
Nasrallah said it was necessary for all Lebanese to remain calm.
"The atmosphere is tense because of the events of recent days," he said. "Everyone is urged not to make matters worse."
Ex-premier Saad Hariri, who heads the anti-Assad opposition in Lebanon, denounced the kidnapping and called for the men's immediate release.
"We condemn the kidnapping of our Lebanese brothers in Syria, regardless of the party behind the kidnapping, and we call for their immediate release," he said in a statement.