DAMASCUS (AFP) ― Violence in Syria cost at least 15 lives on Saturday as a U.N. force to oversee a truce neared half its planned strength, monitors said.

In Idlib province, a stronghold near the Turkish border of rebels fighting President Bahar al-Assad’s regime, security force gunfire killed a man and a woman during a series of raids, the Syrian Observatory for Human Rights said.

Another civilian and a child were killed in pre-dawn shelling in central Hama province, the Britain-based watchdog said, while a fifth was killed by sniper fire in the northeastern city of Deir Ezzor.

Meanwhile, nine soldiers and an army deserter were killed in clashes between rebel groups and regime forces in Idlib province, according to the Observatory.

For its part, state news agency SANA said authorities thwarted an infiltration attempt by an “armed terrorist group” from Turkey and entered the Idlib city of Jisr al-Shughur.

Syrian forces killed and wounded a number of the “terrorists,” as the rest fled back into Turkey, SANA added, saying the groups’ weapons had been seized and RPG launchers and machineguns.

Elsewhere, troops also clashed with rebel fighters in the flashpoint central province of Homs, in southern Daraa province, and in several areas of Damascus province.

Turkey’s Anatolia news agency reported two Turkish journalists who were held in Syria for two months before being freed thanks to Iranian mediation arrived in Tehran on Saturday.

Reporter Adem Ozkose and cameraman Hamit Coskun were flown to Tehran from Damascus, and the two men told Anatolia they were in good health.

A military court, meanwhile, has released eight activists, including blogger Razan Ghazzawi, until their May 29 trial on charges of “possession of banned publications,” human rights lawyer Anwar Bunni said on Saturday.

The persistent violence came as the U.N. mission in Syria said it now had 145 military observers on the ground, just shy of half the force of 300 authorized by the Security Council. They are backed by 56 civilian staff.

The observers are tasked with shoring up a ceasefire brokered by U.N.-Arab League peace envoy Kofi Annan that was supposed to take effect on April 12 but which has been broken daily.

On Thursday, twin suicide bombings in the capital killed at least 55 people and wounded 372 ― the deadliest attacks since the uprising against Assad’s regime erupted in March 2011.

Al-Nusra Front, an Islamist group unknown before the Syrian revolt, released a video on Saturday claiming responsibility for the attacks as revenge for regime bombing of residential areas in several parts of the country.

Claims by the group, including for past bombings, have been hard to verify. In the latest video, the speaker’s voice was electronically modified and no militants were visible.

State media have accused the West and its regional allies of opening the door to Al-Qaeda through its backing of the opposition.

And Information Minister Adnan Mahmud denounced what he called a “terrorist escalation,” which he said was born of “the terrorist and bloody alliance between armed bands and Al-Qaeda, with states in the region and the West who arm and finance them.”

But the main opposition coalition, the Syrian National Council, has accused the authorities of resorting to the “terrorism” itself in a bid to torpedo Annan’s peace plan.

According to the Observatory, another 17 people were killed in violence on Friday, including 12 civilians, while the total death toll has climbed to more than 930, over two-thirds of them civilians, since the battered ceasefire.