Israel limits civilian traffic around Gaza in fear of Palestinian reprisals
Bassam al-Saadi was detained on Monday during an Israeli raid in the occupied West Bank city of Jenin, during which 17-year-old Palestinian Dirar al-Kafrayni was shot dead by Israeli forces.
Saadi's son-in-law, Ashraf al-Jada, was also arrested in the raid. Saadi's wife sustained injuries during the arrest and was taken to hospital for treatment.
Security camera footage of Saadi's arrest showed Israeli soldiers dragging the 62-year-old along the ground.
He was also reported to have been injured by an Israeli army dog.
As news of the fatal raid spread, crowds began to gather in Jenin refugee camp and the nearby city of Nablus, as supporters voiced solidarity with the highly respected figure. Islamic Jihad, seen as the second most influential Palestinian armed resistance group behind Hamas, said it has put its fighters everywhere on alert.
The Israeli army said on Tuesday it was preventing civilian access to areas near Gaza "due to a direct threat".
Saadi is the most senior Islamic Jihad figure in the West Bank, where the armed group has been the main force behind growing armed resistance in Jenin and Nablus.
A former prisoner long wanted by Israel, Saadi and his family have been a critical part of the Palestinian resistance movement in Jenin.
Saadi's great uncle, Farhan al-Saadi, led a rebellion against British authorities in 1936.
As part of its security measures, Israel also closed its only border crossing for people entering or leaving Gaza on Tuesday, while the government said Prime Minister Yair Lapid was reviewing security.
The Israeli army said it deployed reservist troops to assist in keeping civilians safe.
Israel has maintained a crippling blockade of the Gaza Strip since 2007, which critics say amounts to collective punishment of the enclave's two million residents.
Israel prevents the importing of materials and equipment into Gaza and has imposed strict restrictions on exports, leading to a state of "paralysis" in several sectors of Gaza's economy.
Egypt also upholds the siege, controlling movement in and out of Gaza on its border.