Damascus, Syria (CNN) -- Syrian security forces fired the shells that killed French journalist Gilles Jacquier on Wednesday, a Syrian opposition group said, rejecting claims that the France 2 TV journalist was killed by "armed terrorist" fire.
Jacquier, the first Western journalist to die in the 10-month-old uprising in Syria, was killed when a mortar shell struck the pro-government rally he was attending as part of a government-authorized tour of Homs, his network said.
Eight Syrians also died in the attack.
The Syrian Revolution General Commission said security forces fired two shells from an infantry fighting vehicle at a crowd of journalists.
The group said government forces killed at least 24 Syrians Wednesday and injured hundreds more. Another opposition group, the Local Coordination Committees in Syria, put the number at 25 dead.
As the violence went on, Syria's president turned up at a boisterous pro-government rally in Damascus, whipping up his followers and again underscoring his view that the months of popular unrest in his nation are the result of a "conspiracy."
"We will triumph over this conspiracy," Bashar al-Assad told a cheering, clapping and flag-waving throng.
"I will not say that the country is confronting a major conspiracy because you are here to stand up against it," he said. "These are the final phases of the conspiracy, and we will make sure that we will stand up victorious."
Al-Assad's appearance at the rally comes a day after he delivered a defiant televised speech, strongly defending his government's reforms and blaming the unrest on "external conspiracies."
Wednesday's rally in Damascus occurred during an Arab League fact-finding mission to see if the Syrian government is adhering to an agreement to end the violence.
Al-Assad made the appearance amid widespread grass-roots and international anger over his government's crackdown against peaceful protesters. The crackdown has continued despite the presence of Arab League observers and international pressure, with opposition activists estimating the number of dead at 6,000-plus.
Four members of the Syrian army were killed when a bomb exploded in a military bus Wednesday, the state-run Syrian Arab News Agency said. Eight others were injured in the explosion in the Damascus countryside, according to SANA. It blamed the attack on an "armed terrorist group."
Opposition groups blame the violence on al-Assad's government, but the president continues to blame the bloodshed on terrorists.
Al-Assad -- who rarely makes public appearances -- caused quite a stir when he showed up at Wednesday's rally. A news anchor said his presence "caught us off guard, quite surprising."
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 the international news media, to travel freely around Syria.
Arab League officials have pledged to add to their 165 observers already in the country. But the group's mission has been met with skepticism from both al-Assad supporters and anti-government activists.
Anwar Malek, an Algerian Arab League observer who withdrew from the monitoring team, told Al-Jazeera he quit because he found himself "serving the regime, and not part of an independent monitoring body. "
He said the mission is providing the "regime cover for more killing." Malek said he spent 15 days in the restive city of Homs and saw "shameful scenes," finding people in detention facilities in a "deplorable and tragic state."