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 spiraled 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.