U.S. special forces are assisting Philippine troops in their operations against Islamic militants in the southern city of Marawi, the U.S. embassy in Manila said in an emailed statement.

The assistance helps military commanders in their fight against the militants and was offered at the request of the Philippine government, according to the statement, which didn’t give details.

Philippine Defense Secretary Delfin Lorenzana and President Rodrigo Duterte’s spokesman, Ernesto Abella, didn’t respond to calls and text messages seeking comment.

“We routinely consult with our Filipino partners at senior levels to support the Duterte administration’s counterterrorism efforts,” according to the statement.

“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.”

Col. Edgard Arevalo, chief of public affairs of the Armed Forces of the Philippines, said 13 soldiers died and 40 were wounded in a 14-hour battle between marines and the Islamic militants in one of the villages in Marawi City, in the southern island of Mindanao.

Philippine troops have been battling the Maute group, which claims allegiance to the Islamic State, in Marawi for more than two weeks. Mindanao was put under martial law to prevent the hostilities from spreading.

Military spokesman Brig. Gen. Restituto Padilla said at a televised briefing Friday that government troops will seek to facilitate Marawi’s liberation by Monday.