Heavy clashes and bombardment rocked the southern Gaza city of Rafah Saturday, as the UN said 800,000 people had been "forced to flee" an Israeli assault.Philippe Lazzarini, head of the UN agency for Palestinian refugees UNRWA, said that since Israel's Rafah operation began, there had been a massive movement of people."Nearly half of the population of Rafah or 800,000 people are on the road having been forced to flee since the Israeli forces started the military operation in the area on 6 May", he said in a post on X.He said people were fleeing to areas without water supplies or adequate sanitation.Hamas's armed wing, the Ezzedine Al-Qassam Brigades, said it fired a barrage of rockets towards Israel's port of Ashkelon and targeted an Israeli command centre at the Jabalia refugee camp in northern Gaza.An AFP reporter said air strikes and artillery pounded eastern Rafah as warplanes overflew the city on Gaza's border with Egypt.More than 10 days into the Israeli operation in Rafah that sparked an exodus of Palestinians, fighting between Israeli forces and Palestinian militants has also flared again in northern Gaza.Hamas slammed what it called Israel's "escalating crimes of the occupation" and "intensified brutal raids" on Jabalia, saying they had killed dozens of civilians and wounded hundreds more.Aid groups say Israel's Rafah incursion, launched despite overwhelming international opposition and as mediators were hoping for a breakthrough in stalled truce talks, has worsened an already dire humanitarian crisis.With key land crossings closed or operating at limited capacity because of the fighting, some aid began entering Gaza via a temporary US-built floating pier.The Israeli army said 310 pallets began moving ashore in "the first entry of humanitarian aid through the floating pier".Satellite pictures showed more than a dozen trucks lining up Saturday on the pier's approach road.In the coming days, around 500 tonnes of aid are expected to be delivered to Gaza via the pier, according to US Central Command.But UN agencies and humanitarian aid groups have warned sea or air deliveries cannot replace far more efficient truck convoys into Gaza, where the UN has repeatedly warned of looming famine.Israel's offensive has killed at least 35,386 Palestinians in Gaza, mostly civilians, according to data provided by the Hamas-run territory's health ministry.The toll includes at least 83 deaths over the past 24 hours, said a ministry statement Saturday.Palestinian sources in Rafah said Israeli forces were operating in the Al-Salam and Jenina neighbourhoods as well as on the Philadelphi route along the Egyptian border."Troops are advancing and retreating around these areas," a security source said.Cairo, which has been involved in mediation efforts, says a potential Israeli takeover of Philadelphi could violate the two countries' landmark 1979 peace deal.In northern Gaza's Beit Lahia, witnesses reported air strikes near Kamal Adwan hospital on Saturday.Its director Hussam Abu Safiya said Friday the facility had received "large numbers" of casualties from nearby Jabalia and was running low on supplies.The fuel aid that had reached the hospital was "barely enough for a few days", he told AFP.The World Health Organization has received no medical supplies in Gaza since the Rafah operation began, spokesman Tarik Jasarevic said Friday.— Biden aide visits -On the diplomatic front, US National Security Advisor Jake Sullivan was heading to the region.Sullivan will meet Saudi Crown Prince Mohammed bin Salman on Saturday and Israeli Prime Minister Benjamin Netanyahu on Sunday, National Security Council spokesman John Kirby said.Meanwhile, Israel said it killed two senior Islamic Jihad militants in separate air strikes in the northern West Bank and in Rafah.The armed wing of Islamic Jihad confirmed a local commander was killed in an overnight strike on the West Bank's Jenin refugee camp.But there was no immediate comment from the group, which has fought alongside Hamas, on the army announcement that a "significant" operative was killed in Rafah.A military statement did not name him but said he had been involved in "preparing... for operations against IDF (army) ground troops in the area".