The Associated Press

PARIS (AP) — Hundreds of people have gathered in Paris to honor members of an Iranian opposition group killed in an attack on an Iraqi camp.

The exiled group known as the People’s Mujahedeen of Iran or MEK says the attack Thursday on Camp Liberty near the Baghdad international airport killed 23 members. Iraqi authorities say the barrage of rockets also killed three Iraqi soldiers.

No one has claimed responsibility for the attack. U.N. Secretary-General Ban Ki-moon condemned it and urged an investigation.

Maryam Rajavi, who heads the group’s parent organization, France-based National Council of Resistance of Iran, led a commemoration ceremony in Paris on Sunday including hundreds of supporters from different countries.

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