BEIRUT: Lebanon's premier has come under mounting pressure over the kidnapping of Syrian dissidents in Lebanon, with the opposition accusing his government of kowtowing to the regime in Damascus.

"The government of Najib Mikati is employing all diplomatic, security and political channels to back the Syrian regime," said Fares Soueid, secretary general of the Western-backed opposition coalition headed by former prime minister Saad Hariri.

"It is clear that it has become a pawn in the hands of that regime."

Soueid told AFP that as recently as Sunday, two Syrians were arrested at Beirut international airport and handed back to authorities in Damascus, which is battling an eight-month revolt threatening the regime of President Bashar al-Assad.

According to the Syrian opposition, at least 13 dissidents have been kidnapped in Lebanon in the past few months.

"We have been informed of dozens more cases involving Syrians in Lebanon who were kidnapped, beaten up or threatened only because they are opposed to the Syrian regime," said Omar Idlibi, a spokesman for the Local Coordination Committees, an activist network.

"Many of them have urged us not to reveal their names or any details about what happened to them because they don't feel they will get any protection from the Lebanese state," added Idlibi, who is based in Beirut and is also a member of the Syrian National Council, a key opposition group.

The SNC this week sent a letter to Mikati urging him to act on the matter and guarantee the safety of activists who remain in Lebanon.

Mikati, whose government is dominated by the powerful militant group Hezbollah -- a staunch ally of the regime in Damascus -- has acknowledged that kidnappings have taken place but has downplayed them as isolated incidents.

The issue, however, has ignited a firestorm of debate between the pro- and anti-Syria camps in Lebanon.

Idlibi said that one of the most serious cases documented by the Local Coordination Committees involves five activists who fled across the border to Lebanon only to be arrested by Lebanese security forces and handed over to the Syrians.

Two other documented cases involve Shebli al-Aysami, 86, who was last seen in Lebanon in May and three brothers from the Jassem family who went missing in March after one of them was seen in Beirut distributing flyers for an anti-Assad demonstration.

Aysami is co-founder of Syria's ruling Baath party but fled his native country in 1966 over political differences with the group.

Lebanon's police chief last month told a parliamentary committee that he had evidence pointing to the involvement of the Syrian embassy and Lebanese security officers in Aysami's and the Jassem brothers' disappearance.

The embassy has denied involvement.

Some 5,000 Syrians have sought refuge in Lebanon since the revolt in Syria erupted mid-March but many say they now live in fear of being hunted down by Assad's Lebanese allies.

Syria has a long history of meddling in Lebanon's internal affairs and had troops stationed in the country for 29 years until 2005, when it was forced to withdraw amid allegations it was involved in the assassination of former Lebanese premier Rafiq Hariri.

Nadim Houry, Human Rights Watch's senior researcher for Syria and Lebanon, said it was essential for the Lebanese government to take a firm stand on the reported abductions and to launch an independent judicial investigation given the lack of action by the Lebanese judiciary.

"Regardless of its political orientation or ties to Syria, Lebanon has an obligation toward Syrian refugees the same way it has an obligation toward any person fleeing persecution to Lebanon," Houry told AFP.

"Prime Minister Mikati has to state this principle and has to ensure his government respects these obligations but this is not something we have seen so far."