Secretary-General Ban Ki-moon is condemning the attack at an Iraqi camp housing Iranian refugees that killed at least 26 people and wounded many more.

Ban called on Iraq to investigate and bring the perpetrators to justice and reminded the government "of its responsibility to provide for the safety and security of the camp's residents," U.N. spokesman Stephane Dujarric said Friday.

Iraqi police said Thursday that 16 rockets hit Camp Liberty, a former U.S. base housing the exiled Mujahedeen-e-Khalq opposition group, killing three soldiers and wounding at least 16 others guarding the facility.

Saddam Hussein welcomed the Iranian group into Iraq in the 1980s, but Iraq's current Shiite-led government considers their presence illegal.

Ban called on the Iraqi government and international parties to accelerate the relocation of camp residents, Dujarric said.