The Armed Forces of the Philippines on Friday set the country's 119th Independence Day anniversary on June 12 as the next deadline for liberating the southern city of Marawi from militants aligned with Islamic State.
Hundreds of militants, flying the black flag of the Islamic State and led by the self-styled IS emir of southern Philippines, Isnilon Hapilon, and the Maute brothers Omar and Abdullah, were still holed up in the city.
Thirteen Philippine marines have been killed in a gun battle with Islamist militants as troops step up an offensive to regain control of a southern city besieged by the terrorists for nearly three weeks.
The 13 marines were killed during an "intense firefight" on Friday as they were conducting operations to clear enemy positions, military spokesman Lieutenant Colonel Jo-Ar Herrera told a news conference.
More than 40 other marines were injured, he said.
"The local terrorist groups are using the mosque; they are entrenched there".
The plane was dropping the bomb on Islamic extremists who have laid a long siege in a southern city of the country, the military had said.
Without confirming the specific request from the Philippines, a Facebook spokesman said the company has "well-established law enforcement channels for governments to contact us about emergencies".
US Special Operations Forces "have been providing support and assistance in response to Philippine government requests for many years", the embassy said.
The Philippines is majority Christian, but Mindanao has a significant population of Muslims and Marawi City is overwhelmingly Muslim. "There are just providing technical support", Herrera said.
Herrera said the number of troopers killed is "part and parcel of our offensive operations".
Days before the United States embassy issued its statement, Herrera had already confirmed that the United States was providing "techical assistance" to Philippine troops battling local terrorists in Marawi City.
Al Jazeera's Jamela Alindogan, reporting from the Philippine capital of Manila, said that despite Duterte's hostile declarations, the USA military's assistance "comes as no surprise because".
Marine Commandant Maj Gen Emmanuel Salamat confirmed the casualties to GMA News website on Saturday (June 10), saying that government troops and militants from the Maute group had been involved in a 16-hour clash in Barangay Lilod Madaya that began at around 3.30am on Friday.