PHNOM PENH, Cambodia (AP) — Cambodia’s National Assembly on Friday approved a bill making it a crime to deny that atrocities were committed by the country’s genocidal 1970s Khmer Rouge regime, a law that critics allege will be used as a weapon against the political opposition.

The assembly passed the bill unanimously in the absence of opposition lawmakers, who were expelled from the legislature this week. A committee controlled by the ruling Cambodian People’s Party said the opposition lawmakers must relinquish their seats because they had left their old parties to joined a new, merged party to contest the country’s general election in July.