Sign up now for FREE unlimited access to Reuters.com Register WASHINGTON, July 12 (Reuters) – The leader of Islamic State in Syria, one of the militant group’s top five leaders, was killed in a U.S. airstrike, the U.S. military said on Tuesday. In a statement, US Central Command said Maher al-Agal was killed in a drone strike in northwestern Syria and a close aide was seriously wounded. “Extensive planning was done for this operation to ensure its successful execution. An initial review indicates that there were no civilian casualties,” the statement added. Sign up now for FREE unlimited access to Reuters.com Register It said al-Agal was responsible for developing ISIS networks outside of Iraq and Syria. Reuters had earlier reported on the killing, citing US officials. It would be another blow to the Islamist insurgent group’s efforts to reorganize as a rebel force after losing large swathes of territory. The United States has about 900 troops in Syria, mostly in the country’s east torn by a decade of civil war, although President Joe Biden’s administration has yet to spell out its long-term plan for the eight-year mission. The Syrian Civil Defense, a humanitarian organization operating in opposition-held areas, said an unidentified drone targeted a motorcycle in Haltan village in the northern countryside of Aleppo province, killing two people. The US military did not mention a motorcycle in its statement, but said a senior ISIS official closely linked to Maher was seriously wounded during the attack. In February, the top leader of the Islamic State was blown up during a US military strike in Syria. At the height of its power from 2014-2017, the Islamic State ruled over millions of people and claimed or inspired attacks in dozens of cities around the world. Its leader, Abu Bakr al-Baghdadi, declared a caliphate in a quarter of Iraq and Syria in 2014, before being killed in a US special forces raid in northwestern Syria in 2019 as the group collapsed. The US-led coalition fighting Islamic State said in mid-2019, after the group was defeated on the battlefield, that it retained 14,000 to 18,000 members, including 3,000 foreigners, although the exact numbers are as unknown as the same. ISIS. “ISIS continues to pose a threat to the US and partners in the region,” a US Central Command spokesman said in the statement about the drone strike. Analysts say many local fighters may have slipped back into normal life, ready to re-emerge when an opportunity arises. Sign up now for FREE unlimited access to Reuters.com Register Reporting by Phil Stewart and Idrees Ali. Additional reporting by Khalil Ashawi and Maya Gebeily. Editing: Jonathan Oatis, Howard Goller and Mark Heinrich Our Standards: The Thomson Reuters Trust Principles.