The officials, who spoke on condition of anonymity, declined to provide details, Reuters reported. The killing would be another blow to the terrorist group's efforts to reorganize as a guerrilla force after losing large swaths of territory.
In February, the top leader of ISIL blew himself up during a US military raid in Syria.
Maher al-Agal was killed in a US drone strike on Tuesday in northwest Syria, according to US Central Command.
The United States has occupied a large part of Syria in the northeast under the guise of fighting the ISIL, the creation of which was blamed on Washington by the previous president Donald Trump.
MNA