US special forces are helping the Philippine military retake the southern city of Marawi from IS-linked militants, the Philippine army says.
The forces are providing technical help and are not fighting, it said.
President Rodrigo Duterte had earlier threatened to throw out US troops amid strained relations since taking office.
Militants have been under siege since rampaging through the southern city on 23 May. The latest fighting has claimed the lives of 13 Philippine marines.