CAIRO/GAZA — Israeli airstrikes killed at least 21 people, including six children, in Gaza on Sunday, Palestinian health authorities said, ahead of a visit to the region by U.S. Secretary of State Antony Blinken to try to push forward ceasefire talks.

The children and their mother were killed in an Israeli airstrike on a house in the central town of Deir Al-Balah, health officials said. There was no immediate comment from the Israeli military.

The military said it destroyed rocket launchers used to hit Israel from the southern Gaza city of Khan Younis, the scene of intense fighting in recent weeks, and killed 20 Palestinian militants.

Diplomatic efforts to halt the Israel-Hamas conflict and secure a deal to return hostages held in Gaza have intensified in recent days. Talks mediated by the U.S., Egypt, and Qatar are set to continue this week in Cairo, following a two-day meeting in Doha last week.

Making his 10th trip to the region since the war began last October, Blinken was due in Israel on Sunday, days after the U.S. put forward bridging proposals that the mediating countries believe would close gaps between the warring parties.

There has been increased urgency to reach a ceasefire deal amid fears of escalation across the wider region. Iran has threatened to retaliate against Israel after the assassination of Hamas leader Ismail Haniyeh in Tehran on July 31.

At Al-Aqsa Hospital in Deir Al-Balah, relatives gathered around the bodies of the mother and her six children, who were wrapped in white shrouds bearing their names. The youngest was aged 18 months, their grandfather Mohammed Khattab told Reuters at the funeral.

"What was their crime? ... Did they kill a Jew? Did they shoot at the Jews? Did they launch rockets at the Jews? Did they destroy the state of Israel? What did they do? What did they do to deserve this?" said Khattab.

Israel has denied targeting civilians as it hunts down Hamas militants, accusing the group of operating from civilian facilities including schools and hospitals. Hamas denies this.

After 10 months of war, Palestinians in the Gaza Strip are living in constant desperation to find a safe place.

"We are tired of displacement. People are being pushed into narrow areas in Deir Al-Balah and Al-Mawasi, which have become pressure cookers," Tamer Al-Burai, who lives in Deir Al-Balah with several relatives, told Reuters via a chat app. Tanks were just 1.5 km (0.9 miles) away, Burai added.

On Friday, the military ordered the evacuation of areas north of Khan Younis and east of Deir Al-Balah where hundreds of thousands of people displaced by earlier fighting had been sheltering in dire conditions.

The United Nations Office for the Coordination of Humanitarian Affairs said Friday's orders, which included other parts of Gaza outside the humanitarian zones, had reduced the size of the "humanitarian area" designated as safe by Israeli forces to about 11% of the total area of the territory.

The Deir Al-Balah municipality, estimating the current population in the city at 1 million, said the evacuation orders meant more people were crammed into a smaller space.

Additionally, water shortages loomed as several water wells and tankers that used to provide residents with 60% of supplies were located in the areas under evacuation orders, the municipality said in a statement on Sunday.

In Israel, Blinken was due to meet with Israeli Prime Minister Benjamin Netanyahu and other senior officials.

Netanyahu's office described the talks as "complex" and said it was "conducting negotiations, not giving way in negotiations." Israel remained firmly committed to principles established for its security in the May 27 outline proposals, it said in a statement following a meeting of the cabinet.

"I would like to emphasize: We are conducting negotiations and not a scenario in which we just give and give," Netanyahu told the meeting. "There are things we can be flexible on and... things that we cannot be flexible on, which we will insist on.

"Strong military and diplomatic pressure are the way to secure the release of our hostages," Netanyahu said.

Hamas said that optimistic U.S. comments were "deceptive"