Israeli Prime Minister Benjamin Netanyahu announced on Wednesday that Mohammed Sinwar, the Hamas leader in Gaza and younger brother of the late Yahya Sinwar, has been killed, according to Reuters.

The announcement follows an earlier statement on May 21, when Netanyahu said Israel had “probably” eliminated Sinwar amid a series of airstrikes targeting Hamas leadership, as reported by CNN. At that time, Israel launched a major strike on the European Hospital in Khan Younis, killing 28 Palestinians and injuring more than 50, according to the Palestinian Ministry of Health.

Mohammed Sinwar was a key figure within Hamas, known as “the Shadow,” and had survived multiple assassination attempts over the years. Born in 1975 in Khan Younis, he joined Hamas in the late 1980s or early 1990s and was considered one of the group’s most elusive leaders, according to reports by the New York Times and Al Jazeera. He is considered to be one of the architects behind the October 7 attack, and had previously mentioned the idea of taking hostages in interviews.

His death marks another significant blow to Hamas’s leadership following the killing of his brother Yahya Sinwar by Israeli forces last October.

The Israeli military said its forces struck a Hamas command center reportedly beneath the European Hospital in Khan Younis, where several people were killed and dozens wounded, as reported by the Gazan health ministry.