BAGHDAD (AP) — The Latest on developments in Iraq (all times local):

11:20 a.m.

An Iraqi official says a senior Iranian Revolutionary Guard commander has been killed in an explosion during clashes with the Islamic State group west of Mosul.

The Iraqi official says Gen. Shaaban Nasiiri was an adviser to Qassem Soleimani, the head of Iran's elite Quds Force, who has acted as a key adviser to Iraq's Popular Mobilization Forces — an umbrella group of Mostly Shiite militia forces sanctioned by the Iraqi government — in the fight against IS.

The Iraqi official. Speaking on condition of anonymity in line with regulations, said Nasiiri was killed Friday night.

While U.S.-backed forces have fought inside Mosul during the operation to retake it from IS, Iraq's Popular Mobilization Forces have largely operated in the deserts to the west cutting supply lines and attempting to begin securing Iraq's border with Syria.

10:10 a.m.

Aid groups say they are concerned for the safety of civilians following calls from Iraq's government for residents of the Islamic State group-held Old City to flee the area immediately.

The United Nations says in a statement Saturday that "as many as 200,000 additional people may try to leave in coming days" and that both Iraqi forces and IS fighters are obligated under international law to protect civilians.

Save the Children warned that fleeing civilians could be caught in the crossfire, leading to "deadly chaos."

Since the Mosul operation was launched, Iraqi forces have encouraged civilians to remain in their homes to avoid massive displacement and IS fighters have repeatedly targeted fleeing civilians with small arms and mortar fire.

More than 100,000 civilians are estimated to still be inside Mosul.