They include several militant groups pledging allegiance to the Islamic State in 2014, and the group releasing its first video about the Philippines in June 2016, according to a new report released by the U.S. Military Academy's Combating Terrorism Center.
"They did not speak Maranao (the local Muslim dialect), so I knew they would have been slaughtered", Lidasan said.
The militants have defied a US-backed military onslaught, which has seen relentless bombing of the residential areas of Marawi where they are holed up.
Harvey, who has been covering the battle between the Philippines military and Islamic State (IS) militants in Marawi, received medical treatment after being struck in the neck by a bullet.
It was not clear how close to the battle zone the US troops were.
President Duterte said he has been informed by his security officials that the attack in the Philippines had been ordered by the leader of the Islamic State, Abu Bakr al-Baghdadi, just before he was reported killed in an air strike in Syria last Saturday.
Most of the fighting has been confined to one section of the city, but there have been skirmishes and sniper fire in many areas.
"The only issue here is that when the military operation began in Marawi, the president has instructed the chief of staff and the secretary of national defense to do all they can to defeat this threat", Padilla said Wednesday.
"In 2014, we canceled the named operation that we had down there, out of perhaps a premature view that we were gaining success", Mattis testified before a Senate Armed Services subcommittee.
The US's support for the Philippine military is coming despite strained ties between Washington and Manila and former calls by Duterte that he wanted US troops out of his country.
Authorities also said 100 militants remain in the besieged area, down from the 400 to 500 estimated number of fighters during the peak of the siege.
The violence in the lakeside city has left 202 gunmen, 58 soldiers and policemen and 26 civilians dead, officials say.
Adiong told reporters on Monday that people will die in gunfire leaving the city or die inside hiding from it from starvation, because they have no other choice.
Galvez's comment was a refutation of an earlier claim made by Amaq, the IS news organization, that jihadists still hold "more than two-thirds" of the town after 23 days of fighting.
Arevalo confirmed reports that the militants are separating the Christians from the Muslims.
The Philippines has been fighting twin insurgencies from Maoist-led rebels and Muslim separatists in the south for almost 50 years.