HOUSTON (AP) — The gymnasium at the Champions Islamic Center is covered with mats and blankets, donated clothes and boxes of food lining its walls.

On the eve of the Eid al-Adha festival, one of Islam's holiest days, it's become the temporary home for 15 of the thousands of Harvey evacuees, Muslim and non-Muslim. And though it will host hundreds of people during the Friday morning prayer for the so-called festival of sacrifice, the mosque's leaders have been adamant: No matter how many people attend the prayers, the evacuees aren't going anywhere.

"They are the No. 1 priority. They will not be...