A Palestinian police officer walks at the commercial crossing of Kerem Shalom which has been shutdown by Israel since Tuesday, in the southern Gaza Strip August 4, 2022.
A Palestinian police officer walks at the commercial crossing of Kerem Shalom which has been shutdown by Israel since Tuesday, in the southern Gaza Strip August 4, 2022. Reuters / IBRAHEEM ABU MUSTAFA

Gaza's sole power plant will have to shut down within 48 hours if a blockade imposed by Israel is not lifted, officials warned on Thursday, as border tensions simmered following the arrest of a Palestinian militant leader.

Israeli authorities have closed all crossings into Gaza, cutting off access for the fuel trunks that supply the plant, over fears of retaliation attacks following Monday's arrest of Bassam Al-Saadi, a senior leader of the Palestinian Islamic Jihad group.

Already facing cuts that leave them with just 10 hours of electricity a day, Gaza residents would face further blackouts if the plant stopped operating, leaving the enclave's only external source of power a daily feed of 120 megawatts that comes from Israel.

"That would have a grave impact on the daily life of over two million people and vital services," said Mohammad Thabit, of Gaza's power distribution company.

As well as stopping the transport of goods and aid into Gaza, the shutdown - which entered its third day on Thursday - has also prevented workers from crossing into Israel. Residents on the Israeli side have complained of restrictions on movement.

Egyptian mediators stepped up efforts with Israel and Palestinian Islamic Jihad to lower tensions after Saadi's arrest during a raid in the West Bank city of Jenin, in which a 17-year-old member of Islamic Jihad was killed.

The militant group declared full alert among its fighters, implying a threat of imminent retaliation, after footage circulating in Israeli media appeared to show Saadi may have been hurt during his arrest.

"We are in contact with Egyptian officials but so far there is no satisfactory result, therefore, the full alert status remains," said Daoud Shehab, an Islamic Jihad spokesman.

Abdel-Latif Al-Qanoua, a spokesman for Hamas, the militant group that rules Gaza, condemned Israel's closures and said his group had also been in talks with mediators.

"We will not accept the continued closure of crossings and the policy of collective punishment," he said.

Israeli officials have so far offered no comment on the circumstances of Saadi's arrest and suggested the blockade will remain in place while the Islamic Jihad threat persists.