A prominent Shia Muslim clan in Lebanon has abducted several Syrians it says are rebel fighters in retaliation for the kidnapping of one of their relatives by the rebel Free Syrian Army in Damascus, a family member said on Wednesday.

Maher Al-Meqdad said more than 20 Syrians had been seized overnight in Lebanon, including a lieutenant who deserted from President Bashar Al-Assad's army to join the rebels, but those who were not FSA members had been freed.

He gave no details of how or where the men were abducted, but the family was expected to make an announcement later on Wednesday.

Meqdad said the abductions were a response to the capture of Hassan Al-Meqdad in Damascus two days ago by the Free Syrian Army, which said he had been sent to Syria by Lebanon's Shia militant group Hezbollah, one of Assad's regional allies.

He said Meqdad went to neighbouring Syria more than a year and a half ago - that is, before the outbreak of the 17-month-old uprising against Assad - and had no links to the fighting in Syria.

"We don't care what is happening in Syria. We respect the will for democracy. We just want our son to come back to Lebanon safely," Maher Al-Meqdad said.