Syrian helicopter gunships killed at least six people Friday when they dropped barrel bombs on the strategic rebel stronghold of Yabrud, close to the Lebanese border, a monitoring group said.

The Syrian Observatory for Human Rights said the attacks followed a string of raids by regime warplanes around the town, which the army is trying to recapture.

The 10-year-old son of a businessman was abducted at gunpoint on Friday in the eastern city of Zahle, the state-run National News Agency reported.

According to NNA, Michel al-Saqr was heading to school with the family's driver when four masked gunmen in a Grand Cherokee SUV kidnapped him.

The brutal war in Syria could grind on for a decade as Iran and Russia prop up President Bashar Assad's regime and jihadist groups flood the battlefield, experts warned Thursday.

Assad has chosen a deliberate "Machiavellian strategy" of standing by while militant groups such as al-Nusra and the Islamic State of Iraq and the Levant flourish, leaving the U.S.-backed moderate opposition fighting on two fronts, lawmakers were told.

Saudi state television has for the first time broadcast the "confessions" of a jihadist who returned from Syria, as the Muslim kingdom distances itself from Islamist radicals in that country's conflict.

Sulaiman al-Subaie, 25, who grew popular in his homeland for his posts on video-sharing app Keek, reportedly joined the most radical group fighting in Syria, the Islamic State of Iraq and the Levant (ISIL), last August.

Negotiators have lost contact with a group of nuns kidnapped from a Syrian town last year after their captors moved them, a source told AFP on Thursday.

The 13 nuns and three maids were kidnapped from the famed Christian hamlet of Maalula last year and transported to the nearby town of Yabrud, a rebel stronghold the army is fighting to recapture.

Syria's President Bashar Assad has expressed his "solidarity" with Russian President Vladimir Putin's position on the crisis in Ukraine, state media reported on Thursday.

In a telegram, Assad "expressed... Syria's solidarity with Putin's efforts to restore security and stability to Ukraine in the face of attempted coups against legitimacy and democracy in favor of radical terrorists", state news agency SANA said.

A Syrian raid targeted on Thursday the eastern town of Khirbet Younine on the outskirts of Arsalfor the second day in a row.

According to Voice of Lebanon radio (93.3) the airstrike targeted opposition gunmen in the area.

At least five people were killed and more than 20 wounded on Thursday in a bomb blast near a security headquarters in central Syria's city of Hama, a monitor said.

"A truck packed with explosives detonated... near a branch of the military intelligence, killing at least five people and injuring more than 20," the Syrian Observatory for Human Rights said.

The Syrian opposition rejected a proposal by former U.S. Ambassador to Syria Robert Ford for the rebels to negotiate with Hizbullah and other factions fighting alongside President Bashar Assad's troops as part of a political solution to the civil war.

In remarks published Thursday, the spokesman of the Syrian National Coalition, Louay Safi, said: “We only negotiate with the Syrians and we won't accept the participation of foreign militias that kill the Syrian people in the political solution.”

A ship Israel said was carrying advanced rockets bound for Gaza from Iran will be brought into port Saturday after being intercepted by Israeli naval forces, the military said.

"This ship, which was transporting dozens of M302-type rockets with a range of 150 to 200 kilometers (more than 100 miles) is currently north of Port Sudan and will arrive in Eilat Saturday evening," General Motti Almoz told military radio Thursday.