WASHINGTON: US Secretary of State Antony Blinken told two top Israeli officials on Monday of the "unacceptably high" civilian casualties in Israel's bombardment of the besieged Gaza Strip, his spokesman said.

The Israeli military has launched several deadly attacks in recent days including on a refugee camp and multiple UN-run schools where civilians were sheltering.

In response, Hamas said it was pulling out of ceasefire negotiations, causing prospects for a truce and hostage release deal to dwindle further.

Blinken received two influential Israeli officials - Strategic Affairs Minister Ron Dermer and National Security Advisor Tzachi Hanegbi - "to express our serious concern about the recent civilian casualties in Gaza".

Casualties "still remain unacceptably high. We continue to see far too many civilians killed in this conflict", State Department spokesman Matthew Miller told reporters.

On Saturday, Israeli strikes killed more than 90 people in the Al-Mawasi camp near Khan Younis, the Health Ministry in Hamas-run Gaza said.

AFP reported sirens wailing and women screaming as children were pulled bloody and unmoving from the wreckage in Al-Mawasi, which Israel had declared a "safe zone".

The Israeli military said the bombardment targeted two people - the head of Hamas's military wing, Mohammed Deif, and his close associate Rafa Salama who the army said was killed.

A Hamas official said on Sunday that Deif was "well and directly overseeing" operations, though doubts remained.

The two Israeli officials told Blinken that "they do not have certainty yet" about Deif's fate, according to Miller.

The bilateral discussions also focused on a ceasefire between Israel and Hamas, humanitarian aid for Gaza and post-war plans, he said.

The visit comes several few days before Israeli Prime Minister Benjamin Netanyahu is expected to address the US Congress on July 24.

"We continue to hear from Israel directly that they want to reach a ceasefire and that they're committed to the proposal that they put forward," Miller said.

The United States has strongly defended Israel since the Oct 7 attacks by Hamas, in which 1,195 people, mostly civilians, were killed, according to an AFP tally based on Israeli figures.

During the attack, the fighters also seized 251 hostages, 116 of whom are still in Gaza, including 42 the military says are dead.

Israel's military offensive has killed at least 38,584 people, also mostly civilians, according to data provided by the Gaza Health Ministry.

US President Joe Biden has been under mounting political pressure over the plight of Palestinians in the Gaza Strip.

"We are incredibly troubled by the ongoing deaths of Palestinians in Gaza," Miller said Monday, when asked about US weapons provided to Israel.

 - AFP