A former military base in Iraq housing exiled Iranian opposition members has come under intense rocket fire, Iraqi and Iranian officials say, according to BBC News.

The People's Mujahedin of Iran says 23 of its members were killed in the attack in addition to three policemen.

About 80 missiles struck the former U.S. base known as Camp Liberty, close to Baghdad airport, according to the PMOI. No group has yet said it carried out the attack.

The People's Mujahedin Organisation of Iran (PMOI) has been in exile since the Islamic revolution of 1979. The PMOI sided with Saddam Hussein during Iran's war with Iraq in the 1980s but fell out with Baghdad after the Iraqi leader was overthrown by a U.S.-led invasion in 2003. The remaining Iranian dissidents, who advocate the removal of Iran's clerical leaders, were moved to Camp Liberty in 2012.

The Camp Liberty base came under rocket fire in December 2013 and in February 2013.

U.S. Secretary of State John Kerry confirmed in a statement that residents of the camp were killed and injured, but he did not specify how many. He said the U.S. government was talking to senior Iraqi officials to ensure that "all possible medical and emergency assistance" is provided to the victims.