U.S. forces are lending technical support to the Philippine military in a bid to end the siege of a southern city by Islamic State-linked militants, the Philippines said Saturday. A military spokesman confirmed the news to the Associated Press but stressed that no U.S. boots were on the ground. “We don’t have adequate surveillance equipment, so we asked the U.S. military for assistance. It’s noncombat assistance,” military spokesman Brig. Gen. Restituto Padilla was cited as saying. Earlier, a spokesperson for the U.S. Embassy said U.S. special operations forces were assisting at the request of Philippine authorities. “The United States is a proud ally of the Philippines, and we will continue to work with the Philippines to address shared threats to the peace and security of our countries, including on counterterrorism issues,” a statement from the embassy said. The southern city of Marawi has been the center of fierce fighting between Philippine forces and extremists since May 23, when a group of fighters who’ve pledged allegiance to the so-called Islamic State occupied buildings and took hostages. The attack has renewed fears of ISIS gaining a foothold in the country and claimed the lives of 58 government troops. Thirteen Philippine Marines were killed in the latest uptick in fighting on Friday, the single biggest loss so far in the three-week battle. Authorities say at least 138 militants have also been killed in fighting so far.