Rodrigo Duterte, president of The Philippines, made the comments during a visit to soldiers hurt in a recent firefight with ISIS-linked Abu Sayyaf.
Officials described Rodrigo Duterte as "overwhelmed" to meet President Donald Trump, who has praised the Philippine leader's war on drugs and ISIS.
The head of the Philippine military said only about 30 militants remained in the formerly ISIS-held city and that victory would come "in a matter of days."
Filipino jihadis wanted to cause the "next 9/11."
Until the last minute, most passengers believed the hijacking was for real.
Jihadis are still battling three months after launching an armed offensive on the southern city.
A new report details the close links between ISIS's leadership and the militants who overran Marawi in May.
It is not the first time the Philippines president has referenced cannibalism.
The jihadi group abducted the Vietnamese sailors last year off the southern Philippine coast.
The Maute Group and other rebels are targeting Christians in the fight to takeover the city.
ISIS claimed responsibility for the shooting via its Amaq news agency.
Earlier, President Donald Trump said Washington was closely monitoring what he described as a "terrorist" attack unfolding in Manila.
The army has used airstrikes and street combat, yet still the Maute Group Islamist militants fight on.
Manila has deployed helicopters and commandoes to retake Murawi from jihadists.
Militants took a local priest and more than a dozen churchgoers and staff hostage.
The militant leader was killed after he traveled to a tourist hot spot on a hostage-taking expedition.
"Our forecast for 2017 is that the threat in this region will grow because of the creation of an IS nucleus in the southern Philippines," defense expert Rohan Gunaratna said.
The group, which murdered two Canadians last year, demanded a ransom for his release.
Police corruption has been in focus since police officers were charged with kidnapping and murdering a Korean businessman.
The Philippines' leader said he would target more "son of a bitch" traffickers and drug dealers.
The International Maritime Bureau said the waters off the southern Philippines have become increasingly dangerous.
The president's threat to impose a firecracker ban achieved a "remarkable" decline in accidents.
In a visit to wounded troops, he asked Abu Sayyaf to come to the negotiating table.