Osama Hamdan, a top Hamas official, said the group is losing faith in the United States to act as a mediator for cease-fire talks with Gaza as pressure to end the war with Israel continues to increase.

Hamdan said that Hamas will only participate in the cease fire conversations if the discussions focus on implementing President Joe Biden’s proposal suggested in May that includes international support.

Hamdan also said Israel was not negotiating in good faith. Hamas said it was skeptical of the U.S. actually applying pressure on Israel to complete a deal.