Israel’s military warned Saturday deadly aerial operations against Palestinian militants in Gaza could last a week, as cross-border fire reverberated for a second day in the worst escalation since last year’s war.

Health authorities in Gaza, controlled by the Islamist group Hamas, said a five-year-old girl was among 13 people killed by the Israeli bombardment, adding that more than 110 others have been wounded.

Israel’s strikes were met with barrages of rockets from the Palestinian side, and cross-border fire continued in both directions on Saturday, stoking fears of a repeat of an 11-day conflict in May 2021 that devastated Gaza.

Daily life in the enclave has come to a standstill, with streets largely deserted and most shops closed. Its sole power station ground to a halt due to a lack of fuel after Israel closed its border crossings days earlier, according to the electricity distributor.

Civilians on the Israeli  side meanwhile repeatedly fled to air shelters, but there were no immediate reports of casualties.

An Israeli military spokesman said its forces were ‘preparing for the operation to last a week,’ and told AFP that the army is ‘not currently holding ceasefire negotiations’.

Sources within Islamic Jihad ruled out a ceasefire soon, with one saying: ‘for the movement the focus is on the battlefield’.

Israel and Islamic Jihad confirmed the killing of Taysir al-Jabari, a key leader of the militant group, in a Friday strike on a building in the west of Gaza city.

Islamic Jihad is aligned with Hamas, but often acts independently. It declared that the initial Israeli bombardment amounted to a ‘declaration of war’.

Jamal al-Fadi, a political science professor at Gaza’s Al-Azhar University, said he expected the violence to end ‘within days’.

‘Islamic Jihad is reacting in a limited manner and by doing so is preventing the occupation (Israeli military) from intensifying its airstrikes,’ he told AFP.

Hamas has fought four wars with Israel since seizing control of Gaza in 2007, including the conflict last May.

Hamas’s moves now could prove crucial, with the group facing pressure from some to restore calm in order to improve living conditions in Gaza.

Mohammed Abu Salameh, the director of Shifa, Gaza City’s main hospital, said medics are facing ‘acute shortages of medical supplies’.

On Friday, the health ministry reported ‘a five-year-old girl, targeted by the Israeli occupation’ was among those killed.

The girl, Alaa Kaddum, had a pink bow in her hair and a wound on her forehead, as her body was carried by her father at her funeral.

Israeli military spokesman Richard Hecht said Friday ‘we are assuming about 15 killed in action’ in Gaza, referring to Palestinian combatants.

The Gaza strikes followed the arrest in the occupied West Bank of two senior members of Islamic Jihad, including Bassem al-Saadi, who Israel accuses of orchestrating recent attacks.

Israel on Saturday broadened its operation against Islamic Jihad, announcing the arrest of 19 people it said were members of the group in the occupied West Bank.