The leader of ISIS in Syria, who is one of the top five leaders of the terrorist group, has been killed in a US air strike, the US military said on Tuesday.

In a statement, US 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.

The killing would be another blow to the group’s efforts to reorganize after losing large swaths of territory.

In February, the top leader of ISIS blew himself up during a US military raid in Syria.