The air and artillery strikes were focused on the northern section of the tiny, crowded enclave, where dozens of people including women and children were killed overnight, Gaza health ministry spokesman Khalil al-Deqran said.
Israel has intensified its bombardment and built-up armour along the border despite growing international pressure for it to resume ceasefire talks and end its blockade of Gaza, where an international hunger monitor has warned of famine.
US President Donald Trump on Friday backed aid for the Palestinians, saying people in Gaza were starving and adding that he expected "a lot of good things" in the next month.
Asked whether he supported Israeli plans to expand the war in Gaza, Trump told reporters: "I think a lot of good things are going to happen over the next month, and we're going to see. We have to help also out the Palestinians. You know, a lot of people are starving on Gaza, so we have to look at both sides."
Prime Minister Benjamin Netanyahu said on May 5 that Israel was planning an expanded and intensive offensive against Hamas as his security cabinet approved plans that could involve seizing the entire Gaza Strip and controlling aid.
An Israeli defence official said at the time that the operation would not be launched before Trump concluded his visit to the Middle East, which ends on Friday.
Israel's declared goal in Gaza is the elimination of Hamas, which attacked Israeli communities on October 7, 2023, killing about 1200 people and seizing about 250 hostages.
Its military campaign has devastated the enclave, pushing nearly all inhabitants from their homes and killing more than 53,000 people according to Gaza health authorities, while aid agencies say its blockade has caused a humanitarian crisis.
Heavy strikes on Friday were reported in the northern town of Beit Lahiya and in the Jabalia refugee camp, where Palestinian emergency services said many bodies were still buried in the rubble.
Israel's military said its air force had struck more than 150 targets across Gaza, saying these included anti-tank missile posts, terrorist cells, military structures and operational centres.
Israel has faced increasing international isolation over its campaign in Gaza, with even the United States, its staunchest ally, expressing unease over the scale of the destruction and the dire situation caused by its blockade on the delivery of food and other vital aid.
On Thursday, US Secretary of State Marco Rubio said Washington was "troubled" by the humanitarian situation in the enclave.
Netanyahu has dispatched a team to Doha to take part in ceasefire talks with Qatari mediators but he has ruled out concessions, saying Israel remains committed to defeating Hamas.
The Hostages and Missing Families Forum, which represents some of the families and supporters of the 58 hostages still held in Gaza, said that Israel risked missing a "historic opportunity" to bring them home as Trump wound up his visit to the Middle East.
"We are in dramatic hours that will determine the future of our loved ones, the future of Israeli society, and the future of the Middle East," the group said in a statement.
