U.S. President Joe Biden says the goal of peace in Gaza appears increasingly elusive, despite the White House and key mediators Egypt and Qatar intensifying efforts to push Israel and Hamas toward a cease-fire deal.

“It’s getting harder,” Biden told reporters Tuesday when asked if a cease-fire and hostage release deal is becoming a more distant possibility.

With additional U.S. military assets deployed to the Middle East, Biden and his officials are pushing for talks to go ahead as planned in Qatar's capital Doha on Thursday, despite Hamas, the Iran-backed Palestinian militant group, saying it will not participate.

Reaching a truce is key to holding back Tehran’s expected attack on Israel in retaliation for the recent killing of Hamas leader Ismail Haniyeh on Iranian soil. Israel did not claim responsibility for the killing but is widely blamed for Haniyeh’s death.

Biden said he expects Iran to hold off its strike if a deal is reached in the next few days.

With fighting between Israel and Hamas raging in Gaza and cross-border fire intensifying between Israel and Hezbollah in Lebanon, many fear a large-scale Iranian attack would trigger wider conflict in the Middle East.

White House Coordinator for the Middle East Brett McGurk is in Cairo and Doha this week, while Senior Advisor Amos Hochstein is in Beirut, to work diplomatically and militarily to deter further escalation by Iran and its proxy groups and to support border de-escalation in the region, White House Press Secretary Karine Jean-Pierre told reporters Tuesday.

Secretary of State Antony Blinken has postponed his departure to the region, orginally scheduled for Tuesday.

To bolster deterrence the U.S. has deployed additional military assets the Middle East, including squadrons of F-35C and F-22 Raptor jet fighters, the USS Abraham Lincoln aircraft carrier, and the USS Georgia submarine.

Hamas not participating

Israel has agreed to participate in the latest round of talks Thursday. However, Hamas has declined, requesting instead a workable plan to implement a proposal it has already accepted.

“Hamas is committed to the proposal presented to it on July 2, which is based on the U.N. Security Council resolution and the Biden speech and the movement is prepared to immediately begin discussion over a mechanism to implement it,” senior Hamas official Sami Abu Zuhri told Reuters.

“Going to new negotiation allows the occupation to impose new conditions and employ the maze of negotiation to conduct more massacres,” he added.

Another Hamas official said the group decided not to participate in the talks because its leaders do not think the Israeli government, led by Prime Minister Benjamin Netanyahu, has been negotiating in good faith.

For weeks, Netanyahu’s own security officials and negotiators have accused him of stalling by reintroducing demands that had previously been eliminated. Netanyahu’s office denies the claim and blames Hamas for the deadlock.

As first reported by the New York Times earlier this week, in late July Israel presented mediators with less flexible conditions to the set of principles it had made in late May.

“There are people who insist that Israel has deliberately stepped it up because it would prefer to drag its allies into a regional conflagration so as to provide the maximum amount of support to Israel,” said Mirette Mabrouk, director of the Egypt and Horn of Africa program at the Middle East Institute.

“The majority of people feel that this would be just a very, very bad idea,” she told VOA.

US, Iran keen to avoid war

While the White House denies that domestic politics is a motivating factor in the cease-fire talks, Democrats are keen to avoid the optics of massive anti-war demonstrations as the party gears up for its national convention on August 19th, when Vice President Kamala Harris and Minnesota Governor Tim Walz will be celebrated as the presidential ticket to rival Republican nominee former President Donald Trump in the November election.

Boxed into a corner with its vows of retaliation, Iran may also be looking for an off-ramp to avoid a wider war, said Michael Singh, senior fellow at the Washington Institute of Near East Policy.

“If it backs down, it will sort of be seen in the region and maybe within Iran to have backed away in the face of U.S. threats,” he told VOA. “However, if it goes ahead with its plan, then it may find itself in a war that it can't win.”

Iran's mission to the United Nations has denied reporting that Tehran is considering sending a representative to Doha to engage in behind-the-scenes discussions with the U.S. while cease-fire negotiations proceed. The White House has not responded to VOA’s request to confirm whether Iran would play an indirect role in talks.

VOA’s Carla Babb and Kim Lewis contributed to this report.