"One of our SF-260 aircraft conducting airstrikes that day was successfully hitting its assigned target in its earlier sorties", Restituto Padilla, an army spokesman, said on Thursday. "It was an accident".
Defense Secretary Delfin Lorenzana said 500 extremists fought in the city and that they had a "big plan" to occupy it.
Speaking on behalf of the hostages, he says, "please consider us", adding, "it's hard" to bear the gunfire and cannons going off around them.
Another major complicating factor was the safety of about 2,000 residents who the local government said remained trapped in the militant-controlled areas, with troops, police and aid workers trying to rescue them.
The reproduction of the story/photograph in any form will be liable for legal action. "Because the reports we got from the civilians in Marawi is they saw a lot of foreign looking fighters", Department of National Defense Sec.
According to Lorenzana, the incident is now under investigation by a panel led by the Armed Forces chief of staff Gen. Eduardo Año to ferret out the truth and hold accountable those involved.
In the document, Mr. Duterte ordered the military to "undertake all measures to prevent and suppress all acts of rebellion and lawless violence in the whole of Mindanao".
"I think it's horrific for the civilian people who are in there and we really hope that both sides can agree that the civilians should be given the opportunity to come out", the deputy head of the ICRC's Philippine delegation, Martin Thalmann, told AFP in Marawi on Wednesday.
Following the incident, the Philippine military has deployed more ground troops and armored vehicles, indicating it could pull back on airstrikes.
Duterte's troops have been bombing the city in a bid to liberate it, though Reuters noted on Thursday that a government airstrike mistakenly killed 11 of its own troops, after a bombing plane missed its target in an operation in the heart of Marawi.
Philippine President Rodrigo Duterte said on Wednesday he would not talk to Muslim rebels who are fighting the military and occupying parts of a southern city, and that he was determined to keep the Islamic State group out of the country.
As of Thursday, the crisis has claimed almost 180 lives: 36 soldiers and policemen, 120 Maute members, including foreign fighters, and 19 civilians.
Amid the concerns about the rising threat of ISIS, Lorenzana said militants from Saudi Arabia, Chechnya, Yemen, Malaysia and Indonesia were among the dead.
Father Teresito "Chito" Soganub, vicar general of Marawi City, and the others were abducted in a cathedral last week; the priest said he was among 200 captives, including children. Indonesian and Malaysian fighters are among those killed.