US President Joe Biden said on Tuesday he believes Iran may not go ahead with a retaliatory attack on Israel if a deal is reached on a Gaza ceasefire and the release of Israeli captives held by Hamas.

Asked whether Iran might abandon its plans to retaliate for the killing of Hamas political chief Ismail Haniyeh in Tehran on July 31 if Israel and Hamas reached an agreement, Biden said, “That’s my expectation.” However, he also said it was “getting harder” to reach an agreement.

Qatar and Egypt plan to host ceasefire talks on Thursday, though Hamas has called for implementation of a ceasefire proposal unveiled by President Biden in May. Israeli officials also continue to believe that Prime Minister Benjamin Netanyahu’s demands are an obstacle to any potential deal.

Meanwhile, documents obtained by the New York Times on Tuesday confirmed that Israel added new demands to the ceasefire proposal that President Biden unveiled last May, in an attempt by Israeli Prime Minister Benjamin Netanyahu to sabotage the chances of reaching an agreement.

The New York Times report said Israeli negotiators believe Netanyahu’s additional demands have created more obstacles to reaching an agreement, a view also acknowledged by Mossad director David Barnea, the Israeli official in charge of the peace talks.

The new demands included an Israeli military vetting mechanism to ensure that displaced Palestinians returning to northern Gaza were not armed and indefinite Israeli control over the Gaza-Egypt border, which is opposed not only by Hamas but also by the Egyptian government.

In response to the New York Times report, Netanyahu acknowledged that the documents were authentic but claimed that he had not added new demands. “The allegation that Prime Minister Netanyahu added new conditions to the May 27 proposal is false,” his office said in a statement.

As for Tehran’s position on the ceasefire and refraining from striking Israel, Reuters reported earlier on Tuesday that Iran may delay its planned retaliatory attack on Israel to allow ceasefire talks to progress. But Iran has also publicly rejected calls from the United Kingdom, Germany and France to reconsider attacking Israel.

Iranian Foreign Minister Nasser al-Kanaani said in response to the Western calls, “Such demands are devoid of political logic, completely contradict the principles and rules of international law, and are exaggerated.” He added, “They amount to overt and practical support for the source of international crimes and terrorism in the region, and encourage and reward the masterminds and perpetrators of genocide, war crimes, and crimes against humanity.” Al-Kanaani added that Iran is “determined to defend its national sovereignty and security, help establish sustainable stability in the region, and create deterrence against the real source of insecurity and terrorism in the region.”

The previous day, the White House said it was prepared for Iran and its potential allies to launch a “major” attack on Israel. The United States has pledged to defend Israel and has deployed additional assets to the Middle East for just that purpose.