KHAN YOUNIS, Gaza Strip (AP) — Internet and telephone services collapsed across the Gaza Strip on Thursday for lack of fuel, the main Palestinian provider said, bringing a potentially long-term communications blackout even as Israel signalled its offensive could next target the south of the territory, where most of the population has taken refuge.

Meanwhile, Israeli troops for a second day searched Shifa Hospital in the north for traces of Hamas. They displayed guns they say were found hidden in one building, but have yet to release any evidence of the central Hamas command centre that Israel has said is concealed beneath the complex. Hamas and staff at the hospital, Gaza’s largest, deny the allegations.

The communications breakdown threatens to worsen the severe humanitarian crisis in southern Gaza, where Israeli airstrikes continue. Food, water and electricity are increasingly scarce, and the UN is struggling with fuel shortages of its own to deliver aid and help hospitals keep operating.

Most of Gaza’s population of 2.3 million is crowded into southern Gaza, including hundreds of thousands who heeded Israel’s calls to evacuate the north to get out of the way of its ground offensive. If the assault moves into the south, it is not clear where they would go, as Egypt refuses to allow a mass transfer onto its soil.

The latest internet and telephone blackout threatens to last long-term. The main provider, Palnet, said it had run out of fuel to run the network, and Israel has barred entry of new supplies. Gaza’s fragile communication network has broken down multiple times during the conflict because of bombardment or shutdowns by Israel, but each time, Gaza authorities were able to quickly get it back working.

Previous blackouts have traumatised Palestinians, leaving them unable to call ambulances or reach dispersed family members to ensure they are alive amid the bombardment. Aid workers say it hampers humanitarian operations and hospitals. The blackout also largely cuts Gaza off from the outside world, making it even harder for international media to cover events on the ground. Some manage to keep up communications using satellite phones or SIM cards that reach the Israeli or Egyptian networks.

The war, now in its sixth week, was triggered by a wide-ranging Hamas attack into southern Israel on October 7 in which the militants killed over 1,200 people, mostly civilians, and captured some 240 men, women and children. Israel responded with a weekslong air campaign and a ground invasion of northern Gaza, vowing to remove Hamas from power and crush its military capabilities.

More than 11,200 Palestinians have been killed, two-thirds of them women and minors, according to Palestinian health authorities. Another 2,700 have been reported missing, with most believed to be buried under the rubble. The official count does not differentiate between civilian and militant deaths, and Israel says it has killed thousands of militants.

The war has inflamed tensions elsewhere. On Thursday, gunmen shot and wounded four people at a checkpoint on the main road linking Jerusalem to Israeli settlements in the occupied West Bank.

The three attackers were killed, according to police, who said the assailants had assault rifles, handguns and hatchets, and were preparing a large-scale attack in Jerusalem.