BEIRUT — Syrian opposition activists said there was no sign of a letup in a crackdown against dissent as an advance team from the Arab League arrived in the country Thursday to prepare for the arrival of observers to assess whether the government is complying with a peace initiative.

Anti-government activists are skeptical that President Bashar Assad’s regime is sincere about implementing the agreement, which calls for a withdrawal of security forces from the streets, the release of political prisoners and dialogue with the opposition. They accuse the government of trying to avoid greater international involvement in a crisis that the United Nations says has killed more than 5,000 people since March.

Syrian officials blame the bloodshed on what they describe as foreign-backed armed gangs.