Updated at 2:22 p.m. ET
BEIRUT - The death of a French journalist in Syria brought new calls Thursday for an independent investigation of the violence in the country after a series of mysterious attacks since December killed scores of people despite the presence of Arab League monitors.
The prospects for such an independent probe are slim in Syria, where the government has barred access by most foreign media except on escorted trips. The Arab League observer mission has been beset by problems and itself criticized as merely providing cover for the regime's crackdown on dissent. Help from the U.N. is unlikely, in part because Syrian allies Russia and China are blocking action against Damascus.
Humanitarian aid has been turned away, as well. On Thursday, Syrian authorities barred hundreds of people from entering the country from Turkey to deliver medicine, food and other aid.
The French government, human rights groups and Syria's opposition demanded an inquiry intoin a barrage of grenades in the restive city of Homs. The award-winning correspondent for France-2 Television was the first Western journalist killed in the 10-month-old uprising.
"The killing of the French journalist raises a number of questions who launched the attacks, what was the purpose?" Nadim Houry, a senior researcher at Human Rights Watch, told The Associated Press. "So at this point, what's important is again to launch a credible investigation."
The governor of Homs formed a committee to investigate Jacquier's killing, the state-run news agency said. But observers say the probe should be international.
Thousands of people, most believed to be unarmed protesters, have been killed in the 10-month-old revolt against President Bashar Assad. But Jacquier's death, along with three suicide bombings in the capital of Damascus since Dec. 23, have added a new dimension to a conflict that already has brought the country to the verge of civil war.
The government has blamed the three attacks on "terrorists" and said the violence proves that a foreign conspiracy is behind the uprising, not peaceful protesters a narrative the government has maintained since the start of the revolt against Assad's authoritarian regime.
The opposition contends forces loyal to the government are behind the bloodshed as a way to tarnish the uprising. They say the brazen attacks are a sign of an increasingly desperate government that needs to terrify Syrians into submission. In the course of the uprising, Assad has portrayed himself as the only force to prevent chaos and the kind of sustained violence that has been so destructive in neighboring Iraq and Lebanon.
"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, a campaigner for online global activist group, Avaaz.
Syria has only recently started issuing short-term visas for a limited number of journalists, who must be accompanied by government minders. Local reporters work under heavy restrictions.
Jacquier was among a group of 15 journalists on the government trip when they were hit by the grenades; up to eight Syrian civilians also were reported killed.
Video posted online appeared to show the aftermath of the attack, with pools of fresh blood in the street and people frantically loading the injured into cars.
Jacquier's colleagues at France-2 said "his courage and his journalistic values earned our admiration." Jacquier was the 2003 recipient of France's Prix Albert Londres, a prestigious reporting award, as well as the 2010 Prix Bayeux for war correspondents.
The opposition called for protests Thursday in his honor, and activists said hundreds of people demonstrated across the country in cold and rainy weather, demanding Assad's downfall.
During the uprising, several Syrian journalists have been killed or tortured as they tried to cover the revolt, which has proven the most serious challenge to the Assad family's 40-year dynasty. With the U.N. estimate of more than 5,000 dead since March, it is among the bloodiest uprisings of the Arab Spring.
The Arab League team began its work in Syria on Dec. 27 to offer an outside view of whether the government is abiding by its agreement to end the military crackdown on dissent.
The mission, however, has been plagued by problems.
Its chief, Sudanese Gen. Mohammed Ahmed al-Dabi, raised particular concern because he served in key security positions under Sudanese President Omar al-Bashir, who is wanted for crimes against humanity in Darfur. That raised questions about whether Arab League member states, with some of the world's poorest human rights records, were fit for the mission to monitor Syria's compliance with a peace plan.
The observers also faced accusations that the Syrian government is interfering in their work. Team member Anwer Malek quit, telling Al-Jazeera of his disgust that the Assad regime was committing "war crimes" against its own people, adding: "The mission was a farce and the observers have been fooled."
Arab League head Nabil Elaraby told the Egyptian private TV station Al-Hayat that the recent reports of violence in Syria are "concerning," but he said the observers' presence has helped reduce the killings in the country.
Violence continued Thursday, with at least 10 people killed, activists said. The British-based Syrian Observatory for Human Rights said two people were killed by pro-regime snipers in the Karm el-Zaytoun district of Homs, four by indiscriminate firing in the eastern city of Deir el-Zour, and four in the towns of Ariha and Saraqeb in northern Syria.
Another activist group, the Local Coordination Committees, put the death toll at more than 20.
Syrian authorities barred hundreds of activists from crossing into the country from Turkey to deliver medicine, food and other aid to victims, said Bilal Dalati, a spokesman for the Freedom Convoy group.
Assad, 46, who inherited power from his father in 2000, gave his first speech Tuesday since June, saying he would strike back with an "iron hand" at those who threaten his rule. He blamed terrorists, saboteurs and the foreign media.
U.S. Secretary of State Hillary Rodham Clinton criticized Assad for his "chillingly cynical speech." Assad is "only making excuses: blaming foreign countries; conspiracies so vast that now it includes the Syrian opposition, the international community, all international media outlets, the Arab League itself," she said.
"We cannot permit President Assad and his regime to have impunity," Clinton added.
International intervention, akin to the NATO intervention that helped topple Libya's Muammar Qaddafi, is all but out of the question, in part because Syria is far more combustible.
Syria has multiple sectarian divisions, largely kept in check under Assad's heavy hand and his regime's secular ideology. Most significantly, most of the population is Sunni Muslim, but Assad and the ruling elite belong to the minority Alawite sect, an offshoot of Shiite Islam.
Syria is a highly unpredictable country, in part because of its sizable minority population, the loyalty of the military and the regime's web of allegiances to powerful forces including Lebanon's Hezbollah and Shiite powerhouse Iran. Serious and prolonged unrest are likely to hurt the regime's proxy in Lebanon Hezbollah and weaken Iran's influence in the Arab world.