The Syrian opposition yesterday demanded that the Arab League replace the head of its observer mission, a Sudanese general linked to accusations of genocide in Darfur.
Gen Mohamed Ahmed Mustafa Al Dabi is a longtime supporter of the Sudanese leader Omar Al Bashir and was his head of military intelligence.
The International Criminal Court has indicted Mr Al Bashir on charges of genocide, war crimes and crimes against humanity.
"What do you expect from the head of a monitoring mission who is accused of genocide in his own country?" said Ausama Monajed, a member of the Syrian National Council, the main opposition group.
"SNC is deeply concerned about having Mr Al Dabi as head of the monitoring mission given the accusations around him and we will put a motion to the Arab League requesting that he be changed."
The 60 Arab League monitors who began work on Tuesday are the first observers allowed in to Syria since an anti-government uprising began nine months ago. Their job is to ensure that the regime of the Syrian president Bashar Al Assad is complying with an Arab League plan to end violent repession that the UN says has killed more than 5,000 people.
The monitors were scheduled yesterday to visit flashpoints around Damascus, the northern and central cities of Idlib and Hama and southern Deraa province.
But as they began, at least four people died when security forces opened fire on tens of thousands protesting outside a mosque in a Damascus suburb, activists said.
The protest was close to a municipal building monitors were visiting.
The continuing violence, and questions about the human rights record of Gen Al Dabi, reinforced the opposition's view that Syria's limited cooperation with the observers is a farce for the regime to buy time and forestall more international condemnation and sanctions.
Rami Abdul-Rahman, head of the British-based Syrian Observatory for Human Rights, said at least 16 people were shot dead by security forces yesterday, most of them in several suburbs of Damascus.
The Local Coordination Committees, another activist group, said 28 people were killed.
Activists say more than 70 civilians have been killed by security forces since the monitors arrived on their month-long mission.
"The situation seemed reassuring so far," Gen Al Dabi said on Wednesday after his team's first foray into Homs, the centre of the uprising.
"But remember, this was only the first day and it will need investigation. We have 20 people who will be there for a long time."
Amnesty International said under Gen Al Dabi's command, military intelligence in the early 1990s "was responsible for the arbitrary arrest and detention, enforced disappearance, and torture or other ill-treatment of numerous people in Sudan".
Joe Stork, of Human Rights Watch, said Gen Al Dabi's role was as point-person in Darfur during the most intense period of conflict in south Darfur.
"He has a lot of experience in obstructing international investigations. That could make him very useful if his head's been turned around, but we don't know if that's the case," Mr Stock said. "It raises questions about what this mission can accomplish."
Haytham Manna, a prominent Paris-based dissident, urged the Arab League to replace Gen Al Dabi or reduce his authority because "we know his history and his shallow experience in the area".
Omar Idilbi of the Local Coordination Committees described Gen Al Dabi as a "senior officer with an oppressive regime that is known to repress opposition" and said there are fears he might not be neutral.
There have been international calls to give the team complete access, which includes the ability to speak unhindered to representatives of the opposition, civil society and prisoners.
On Wednesday, Syrian state media reported the release of 755 prisoners who had been arrested during the protests. More than 2,500 prisoners were also reportedly released last month. But human rights activists say many more have been arrested and the state has failed to provide a comprehensive list of those detained.
Sarah Leah Whitson, of Human Rights Watch, said the release of some detainees was a good sign. But she expressed concern about reports obtained by the rights group that other detainees were being moved, possibly in advance of planned inspections by the monitors.
Ms Whitson also raised concerns about whether the monitors are properly qualified for their mission. She said the Arab League should have offered assurances the group had received training in human rights investigations before being deployed to Syria.
"It's not enough to have once been in government. They need training in finding things that governments are trying to hide," she said.
* With reporting by Omar Karmi in Washington, the Associated Press, Agence France-Presse and the Washington Post