The Philippine leadership was wary of U.S. military activity on its territory.
Officials described Rodrigo Duterte as "overwhelmed" to meet President Donald Trump, who has praised the Philippine leader's war on drugs and ISIS.
President Rodrigo Duterte declared Marawi City liberated six days ago, even though battles were still ongoing.
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."
The news comes as a surprise to multiple Filipino officials, who say they have no knowledge of such an operation.
The controversial leader has repeatedly referenced raping women despite widespread condemnation.
The Philippines military said child soldiers are among the fighters left in the embattled city.