VOI - Voice of Indonesia | RRI - Radio Republik Indonesia

The leader of Islamic State in Syria, who is one of the top five leaders of the militant group, has been killed in a U.S. air strike, the U.S. military said on Tuesday.

In a statement, U.S Central Command said Maher al-Agal had been killed in the drone strike in northwest Syria and a close associate of his was seriously injured.

"Extensive planning went into this operation to ensure its successful execution. An initial review indicates there were no civilian casualties," the statement added.

It said al-Agal was responsible for developing ISIS networks outside of Iraq and Syria.

Reuters had earlier reported on the killing, citing U.S. officials.

The killing would be another blow to the Islamist militant group's efforts to reorganize as a guerrilla force after losing large swaths of territory.

In February, the top leader of Islamic State blew himself up during a U.S. military raid in Syria. (Reuters)