The Iraqi Army said Sunday it has secured the first safe exit route for civilians to leave Islamic State's besieged stronghold of Fallujah, and a Norwegian aid group said thousands of people have already used it to flee on the first day it was open.

Iraq has launched a major operation to recapture Fallujah — an Islamic State bastion just an hour's drive from Baghdad — but the United Nations fears for the fate of up to 90,000 civilians believed trapped inside with little food or water.

The new exit route, known as al-Salam (Peace) Junction, was secured Saturday, southwest of Fallujah, Joint Operation Command spokesman Brig. Gen. Yahya Rasool said.