Israeli forces have pressed deeper into areas of the central and southern Gaza Strip as they battled Hamas fighters, while Palestinian health officials say Israeli strikes killed at least 22 people across the enclave.
The new escalation comes hours after US President Joe Biden pressed Israeli Prime Minister Benjamin Netanyahu on the urgency of sealing a deal for a truce in Gaza and the release of hostages, the White House said.
Months of on-off talks on a ceasefire have circled the same issues but Israel and Hamas have stuck firmly to their demands.
In the northern Gaza town of Beit Lahiya, a strike on a house killed 11 people, while another killed six, including a local journalist, in a house in Al-Maghazi camp in the central Gaza Strip, medics said.
Five others were killed in separate strikes in the south.
The Israeli military said its forces had intensified their operations in Deir Al-Balah, in central Gaza, and Khan Younis, in the south, dismantling dozens of military structures, locating rockets, and killing militants, in the past 24 hours.
It said forces killed 50 militants in the area of Rafah, in the far south of the enclave, in the past day.
A phone call between Biden and Netanyahu late on Wednesday followed a whirlwind trip to the region by US Secretary of State Antony Blinken that ended on Tuesday without producing a breakthrough in the 10-month-old war.
Hamas wants a deal that ends the war in Gaza and releases Israeli and foreign hostages in Gaza in return for the freedom of many Palestinians jailed by Israel.
It blames Israel and the United States for the failure to conclude a deal.
Netanyahu says the war will only end once Hamas is defeated, and a ceasefire to allow the exchange of hostages and prisoners would be only a pause while the militant group remains a threat.
In the central Gaza town of Deir Al-Balah, which houses about one million residents and displaced Palestinians, residents said tanks advanced further from the east and blocked some roads connecting the city with the nearby Khan Younis in the south.
Israeli tanks also advanced to the west, in Al-Karara and Hamad areas of Khan Younis, pushing more families out of their shelters and tents, sometimes under heavy fire from tanks and drones, residents said.
"Last night drones began firing towards the tents, we ducked down, for maybe hours, then the noise of tanks got louder as they advanced closer, so we decided to run," Imad Al-Ghalayeeni, 48, told Reuters by phone from Khan Younis.
"We are five families, 48 persons, we ran to the beach, some slept on the road, others slept onshore, just on the sand with no tents, no blankets or mattresses and you can imagine how terrified were the children and women."
Ghalayeeni said there was growing disillusionment among Palestinians in Gaza about the ceasefire talks.
"These talks are time-wasting, and they aim to give Netanyahu the time he needs to continue what he is doing," he said.
Most of Gaza's 2.3 million population has been displaced multiple times since the start of the war.
Even in areas designated safe zones, there have been regular reports of casualties from Israeli strikes.
Israel's military campaign has killed more than 40,000 people in Gaza since October, according to Palestinian health authorities.
The war began on October 7 when Hamas gunmen stormed into Israeli communities and military bases, killing about 1200 people and abducting about 250 hostages, according to Israeli tallies.
