JERUSALEM/GAZA--Israeli jets struck targets across Gaza late on Tuesday as armed groups there fired rocket barrages toward Israel in response to the death of a Palestinian hunger striker in Israeli custody. Plumes of smoke spiralled into the night sky as the jets hit targets that the Israeli military said included weapons manufacturing sites and training camps of Hamas, the Islamist group that governs the blockaded coastal enclave. At the same time, sirens sounded in southern Israeli towns including Ashkelon, about 14 km (9 miles) north of Gaza. Hamas radio reported that militant factions in the area continued firing rockets in response to the death of Khader Adnan, which sources in the Palestinian group Islamic Jihad said was one of its political leaders. The fighting, about a month after the last cross-border exchange of fire between Israel and Gaza, came after Adnan died early on Tuesday following an 87-day hunger strike in an Israeli prison. Adnan, who was awaiting trial, was found unconscious in his cell and taken to a hospital, where he was declared dead after efforts to revive him, Israel's Prisons Service said. He was the first Palestinian hunger striker to die in Israeli custody in more than 30 years. Hundreds of people took to the streets in Gaza and the occupied West Bank to rally and mourn Adnan's death, which Palestinian leaders described as an assassination. In Gaza, an umbrella group of armed Palestinian factions including Hamas and Islamic Jihad claimed responsibility for a series of rocket barrages fired towards Israel during the day. The Israeli military said at least 30 rockets were fired from Gaza. Two landed in the small Israeli city of Sderot just east of Gaza, wounding three people, including a 25-year-old foreign national who Israel's ambulance service said sustained serious shrapnel wounds. In the West Bank city of Hebron, shops observed a general strike. Some protesters burned tires and hurled stones at Israeli soldiers who fired tear gas and rubber bullets at them. There were no reports of injuries. Since 2011, Adnan conducted at least three hunger strikes to protest detention without charges by Israel. The tactic has been used by other Palestinian prisoners, sometimes en masse, but none had died since 1992. Adnan's lawyer Jamil Al-Khatib and a doctor with a human rights group who recently met him accused Israeli authorities of withholding medical care. "We demanded he be moved into a civilian hospital where he could be properly monitored. Unfortunately, such a demand was met by intransigence and rejection," Al-Khatib told Reuters. Adnan, 45, was a baker and a father of nine from Jenin in the Israeli-occupied West Bank. Islamic Jihad has a limited West Bank presence but is the second most powerful armed group in Hamas-ruled Gaza, where Israeli forces fought a brief war against it last August. Lina Qasem Hassan of Physicians for Human Rights in Israel said she saw Adnan on April 23, at which point he had lost 40 kg (88 pounds) and was having trouble moving and breathing but was conscious. "His death could have been avoided," Qasem Hassan told Reuters, saying several Israeli hospitals had refused to admit Adnan after he made brief visits to their emergency rooms. The Prisons Service said hospitalisation had not been an option as Adnan had declined "even a preliminary inspection". Physicians for Human Rights said Israeli authorities had denied requests by Adnan and his family to visit him in prison. Speaking from the family's home in the northern West Bank town of Arraba near Jenin, Adnan's wife, Randa Musa, said: "Our message to all the resistance groups is, we do not want the weapons that were not used to free the sheikh (Adnan) to be used after his death. We do not want to see any bloodshed." Before one round of rockets, Hamas radio said an Israeli tank shelled one of the group's observation posts in Gaza. "Our fight is continuing and the enemy will realise once again that its crimes will not pass without a response," Islamic Jihad said in a statement.