Damascus last year agreed to let monitors from the Arab League inside the country to ensure the government was honoring a pledge to pull military forces from the streets.
The Syrian government has been the target of near-universal criticism for its brutal crackdown on opponents of President Bashar Assad. Though Damascus claims it's fighting an insurgency, the United Nations estimates more than 5,000 people have been killed by security forces since the uprising began mid-March.
Two unidentified protesters told representatives from Human Rights Watch during in-person interviews Tuesday that security forces opened fire on demonstrators as they tried to meet with Arab League observers in the western city of Jisr al-Shughur.
Anna Neistat, an associate director at Human Rights Watch, said Assad is making fools out of the Arab League.
"Such incidents, and the ever rising death toll, clearly demonstrate that the presence of Arab League observers has done little to compel the Syrian authorities to stop their crimes," she said in a statement.
An Algerian member of the Arab League mission resigned in protest this week, arguing Damascus was using the mission as cover while it continued its assault on the civilian population.
"The time has come for the Arab League to call out the Syrian government on its failure to abide by the agreement," Neistat said.