US President Joe Biden’s main adviser on the Middle East said on Saturday there would be a “significant pause” in fighting if Hamas agrees to release prisoners.

“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 prisoners would result in “a significant pause… and a massive surge of humanitarian relief”, he said.

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

The White House said President 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 prisoners, believed to include about 10 US citizens.

So far efforts by Qatar have led to the release of four of the prisoners.

McGurk said the situation in the besieged Palestinian territory was “horrific” and “intolerable”.

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