The Israeli military struck the southern Gaza city of Khan Younis on Tuesday evening in an attempt to kill Mohammad Sinwar, one of Hamas’s top leaders in the enclave, according to Israeli military officials.

There was no immediate confirmation that Israel was successful.

Throughout the war in Gaza, Israel has sought to eliminate Hamas’s hierarchy, methodically assassinating the group’s top officials. After such killings, the Israeli military has often taken weeks to confirm a target’s death, while Hamas has sometimes taken months.

Here’s what we know about Mr. Sinwar, who has survived such assassination attempts before.

He is Yahya Sinwar’s younger brother.

Mohammad Sinwar was born in Khan Younis in 1975. He is the younger brother of Yahya Sinwar, who masterminded the Hamas-led attacks on Israel that started the war in Gaza in October 2023 and in whose footsteps Mohammad Sinwar followed for much of his life.

Their family fled Ashkelon, Israel, during the 1948 Arab-Israeli war to a refugee camp in Khan Younis.

The younger Mr. Sinwar is believed to have joined Hamas in the early 1990s as Yahya was rising up the organization’s ranks. In 1991, he was arrested by the Israeli military for suspected terror activity, spending less than a year in Israeli custody. He was also jailed for several years in the 1990s in the West Bank city of Ramallah by the Palestinian Authority.

He is known as ‘the Shadow.’

Like his elder brother, Mohammad Sinwar has long been wanted by the Israeli authorities. He is said to have been targeted in six assassination attempts by 2021.