Damascus, Syria (CNN) -- The French foreign minister called Thursday on Syrian authorities to divulge the "whole truth" about the killing Wednesday of a French journalist in the city of Homs.
Alain Juppe told France 2 television that an "investigation must establish the origin of these events, and in particular where the firing came from, who is responsible for this, so that we can then act accordingly."
France 2 TV journalist Gilles Jacquier was killed after a mortar shell struck the pro-government rally he was attending as part of a government-authorized tour of the city, his network said. Eight Syrians also died in the attack.
Juppe said Syria "should have ensured the safety of the journalists who had been invited to carry out that visit."
The state-run Syrian Arab News Agency said Jacquier was among a delegation of international journalists visiting the city's Ekrima neighborhood "to document the damages left by terrorists on building with photos and interviewing citizens who were victims of terror in the city when armed terrorist member fired mortar projectiles on the delegation."
But the Syrian Revolution General Commission, an opposition force, disputed that description of events. It said security forces fired two shells at journalists from an infantry vehicle.
"The journalists were attacked in a heavily militarized regime stronghold -- it would be hugely difficult for any armed opposition to penetrate the area and launch such a deadly attack," said Wissam Tarif, an Arab world campaigner with the activist group Avaaz.
The Syrian National Council said the killing was "an attempt to silence neutral and independent media sources" and called for an independent investigation.
The Arab League has called on Damascus to stop violence against civilians, free political detainees, remove tanks and weapons from cities and allow outsiders, including members of the international news media, to travel freely around Syria.
The monitors' mission, which began December 26, will continue until January 19, said Ambassador Adnan Al Khudeir, head of the operations room to which the Arab monitors report. He put the number of monitors at 163 in 16 teams. One has left because of sickness and another because of personal reasons, he said.
There has been widespread grassroots and international anger over the Syrian government's 10-month crackdown against peaceful protesters that has continued despite the presence of the Arab League observers. Opposition activists estimate the number of dead at more than 6,000.
Meanwhile, the Local Coordination Committees of Syria -- an opposition activist group that organizes and documents anti-government demonstrations -- said a 13-year-old girl from a village in Aleppo was shot and killed by government security forces Friday. The girl was traveling with her family when their vehicle was fired upon at a checkpoint, and she was hit three times.
Security forces forbade the family from taking the girl to a nearby hospital, and she died at the scene, the LCC said.
The LCC said earlier that 25 people in five provinces were killed Thursday: 10 in Homs, nine in Idlib, four in Deir Ezzor, and one each in Hama and the Damascus suburb of Douma. Two of those killed were military recruits who had defected, the group said.
The crackdown and uprising has spawned the formation of the Free Syrian Army, an armed resistance movement composed of military defectors.
The LCC reported 20 soldiers defected Thursday at a checkpoint in Daraa province. It also said "all the officers and soldiers" in the Homs neighborhood of Wadi Al-Sayeh joined the "Free Army" in the neighborhood of Khalidiah.
Arab League officials reacted Thursday to Anwar Malek, an Algerian observer who has withdrawn from the monitoring team. He told Al-Jazeera he quit because he found himself "serving the regime, and not part of an independent monitoring body."
Malek said the mission is providing the "regime cover for more killing." He said he spent 15 days in Homs and saw "shameful scenes," finding people in detention facilities in a "deplorable and tragic state."
But the League's Affifi Abdel Latif Mohamed accused Malek of having "betrayed all ethics and endangered the lives of his fellow monitors on the ground. He has been suspended from the Algerian military and has close ties with Syrian opposition and had his own agenda. He did not leave his hotel to even comment on the mission or its goals. He did this to shine in the media and jeopardized the mission."
The head of its mission, Sudanese Lt. Gen. Mohammed Ahmed al-Dabi, said Malek had been assigned to the Homs team, but did not leave the hotel for six days and did not join his team in the field because he said he was ill, according to SANA. "He clarified that Malek perjured," the story added.
CNN's Brian Walker, Joe Sterling and Journalist Mohamed Fadel Fahmy in Cairo, Egypt, contributed to this report.