Khader Adnan, a major official in the Palestinian militant group Islamic Jihad, died in Israeli detention following an 86-day hunger strike.
According to the Israel Prison Service (IPS), he was discovered unconscious early Tuesday. He was rushed to the hospital, but all attempts to resuscitate him were futile.
According to the IPS, he refused to undergo medical tests and treatment.
Following the announcement of the death, militants launched at least three rockets from the Gaza Strip, but no one was injured.
The Gaza-based Islamic Jihad has previously warned that Israel would “pay a heavy price” if he died in prison.
Khader Adnan, 44, was scheduled to stand trial this month on charges of terrorist group membership and incitement.
Adnan was from Jenin in the occupied West Bank and had spent the last two decades in Israeli captivity.
He’d gone on hunger strike five times before.
Before his death, his wife Randa Mousa said he was “refusing any support, refusing medical examinations, he is in a cell with very difficult detention conditions”.
The fate of Palestinian prisoners in Israel is a top issue for the Palestinians, who hold Israel responsible for their well-being.