US President Joe Biden's main adviser on the Middle East said Saturday there would be a "significant pause" in the Israel-Hamas war if hostages held by militants in Gaza are freed.

"The surge in humanitarian relief, the surge in fuel, the pause… will come when hostages are released," Brett McGurk told a security conference in Bahrain.

Release of a large number of hostages would result in "a significant pause… and a massive surge of humanitarian relief," he said.

Hamas militants seized about 240 hostages on October 7 when they surged across Gaza's militarised border into southern Israel to kill around 1,200 people, mostly civilians, according to Israeli officials.

In response, Israel is carrying out a relentless bombardment and ground offensive of targets in the Gaza Strip which has so far killed 12,000 people, according to the Palestinian territory's Hamas government.

McGurk said Biden had discussed the issue on Friday evening with the ruler of the Gulf nation of Qatar, which is leading mediation efforts towards a ceasefire and release of the captives.

The White House said Biden and Qatar's Emir Sheikh Tamim bin Hamad Al-Thani discussed "the urgent need for all hostages held by Hamas to be released without further delay".

Two days earlier Biden had said he was "mildly hopeful" of reaching a deal to free the hostages, believed to include about 10 US citizens.

So far efforts by Qatar have led to the release of four of the captives. A fifth hostage, a soldier, was rescued in an Israeli operation.

Israel's army said this week it had recovered the bodies of two women hostages in Gaza.

McGurk said on Saturday that the situation in the besieged Palestinian territory was "horrific" and "intolerable".

A senior European official, speaking on condition of anonymity, said that "we have to work" for the release of the hostages and to secure humanitarian pauses.

"If they go together, good. But the important thing is that both things must happen," the official said.

Israel has refused to heed calls for a ceasefire before all the hostages are released.

Jordanian Foreign Minister Ayman Safadi, who also attended the Bahrain conference, said it was "unacceptable" to link humanitarian pauses to a hostage release.

Meanwhile, EU foreign policy chief Josep Borrell reflected on the future of Gaza, saying "Hamas cannot be in control of Gaza anymore".

The Palestinian Authority, based in the occupied West Bank city of Ramallah, "told me they are ready and willing to take this responsibility" with the help of the international community, said Borrell.

He added that Arab countries should also play a role in any future configuration, both political and economic, for Gaza.

Safadi insisted there would be "no Arab troops" deployed in Gaza.