NEW : Prime Minister Nuri al - Hussein says he believes conspirators are plotting to undermine him . At least 20 people are killed in the shootings , health officials and witnesses say . The shootings occur in Falluja in Iraq 's western Anbar province . The protest in Falluja , dubbed `` Friday of No Retreat '' by organizers , is the latest in a series held in predominantly Sunni regions of Iraq . Protesters are calling for the Shiite prime minister to step down .
NEW : Prime Minister Nuri al - Hussein says he believes conspirators are plotting to undermine him . At least 20 people are killed in the shootings , health officials and witnesses say . The shootings occur in Falluja in Iraq 's western Anbar province . Protesters are calling for the Shiite prime minister to step down .