Hapilon leads a radical faction of another Mindanao-based group, the Abu Sayyaf. After the raid, Abu Sayyaf called in reinforcements from the Maute, an allied group.
Solicitor General Jose Calida said Friday that former President Fidel Ramos may have been wrong in suggesting that President Rodrigo Duterte's declaration of martial law should have been limited to certain parts of Mindanao.
Some of those trapped in Marawi had called and text-messaged a hotline pleading with the military to stop the air strikes, according to Zia Alonto Adiong, a local politician coordinating complex efforts to evacuate civilians, dead and alive.
The black flags of the Islamic State group were planted atop buildings and flown from commandeered vehicles, including a government ambulance and an armoured auto, said Mr Mamintal Alonto Adiong Jr, vice governor of Lanao del Sur province, of which Marawi is the capital.
Witnesses said gunmen were flying the black flags of IS.
Hosted by Aljo Bendijo and Kathy San Gabriel, the forum had a resident of Marawi City and political analysts to explain the situation and clarify the need for martial law. "We can not just pinpoint the particular spot". The military says Maute has yet to be endorsed by Islamic State, or ISIS, as one of its affiliates.
Fighters of the Maute group, which has vowed allegiance to the Islamic State, also burned several buildings, including the cathedral, a Protestant school and the city's jail.
Over the past week, the fighters have shown their muscle, withstanding a sustained assault by the Philippine military and increasing fears that the Islamic State group's violent ideology is gaining a foothold in this country's restive southern islands, where a Muslim separatist rebellion has raged for decades.
Nevertheless, Duterte also said on Friday that he was prepared to talk with the group's leaders.
But Acmad Aliponto, a 56-year-old court sheriff who decided not to flee the city, said that while the militants were well-armed, he believes they have little local support, and that the recent violence could turn more people against them.
Political analysts in the panel said the Maute Group has a big following.
He said Hapilon suffered a stroke after a government airstrike wounded him in January.
"My order to the troops is all people who are not authorized by government to carry arms and they resist, kill them, wipe them out", he said. "We have to finish this".
"There exists no doubt that lawless armed groups are attempting to deprive the President of his power, authority and prerogatives within Marawi City as precedent to spreading their control over the entire Mindanao", the report said. "We give primordial concern to the safety of our people, the safety of the Maranao", Herrera said.
An enraged Duterte, who was in Moscow to meet Russian President Vladimir Putin, declared martial law shortly after the fighting erupted and cut short his trip to fly home and deal with the crisis. He also heads an alliance of at least 10 smaller militant groups, including the Maute, which has a presence in Marawi and was instrumental in fighting off government forces in this week's battles.
All of the groups are inspired by the Islamic State group, but so far there is no sign of significant, material ties.
Washington has offered a US$5 million ($7m) reward for information leading to Hapilon's capture.
The admission confirms what observers see as moves by IS targeting the majority Muslim southern Philippines to establish a stronghold in South East Asia.