U.S. and Iranian negotiators have reached an agreement on a 60-day memorandum of understanding to extend the ceasefire and begin negotiations on Iran’s nuclear program, though President Donald Trump has not yet given final approval, Newsmax confirmed Thursday.

The proposed agreement would mark the most significant diplomatic breakthrough since the war began, although additional negotiations would still be needed to address Trump’s demands regarding Iran’s nuclear activities, reports Axios. 

U.S. officials said the terms of the agreement were largely finalized by Tuesday, but both sides still needed approval from senior leadership before signing.

The White House has not commented on the report.

According to the officials, Iranian negotiators later informed mediators they had obtained the necessary approvals and were prepared to sign the agreement. Iran has not publicly confirmed that claim.

The officials said U.S. negotiators briefed Trump on the details of the proposed deal, but the president did not immediately approve it.

“The president relayed to the mediators that he wants a couple of days to think about it,” a U.S. official said.

Trump and his advisers had previously believed they were nearing an agreement at several points during the conflict, but earlier efforts failed to produce a deal.

Under the proposed memorandum, shipping through the Strait of Hormuz would remain “unrestricted,” according to U.S. officials. One official said the provision would prohibit tolls and harassment and require Iran to remove all mines from the strait within 30 days.

The officials also said the U.S. naval blockade would be lifted in stages tied to the restoration of commercial shipping activity.

The memorandum would include an Iranian commitment not to pursue a nuclear weapon, according to the officials. The agreement would also prioritize negotiations over the disposal of Iran’s highly enriched uranium stockpile and the future of Iranian uranium enrichment during the 60-day negotiation period.

Under the proposal, the United States would agree to discuss sanctions relief and the release of frozen Iranian funds as part of the talks. The memorandum would also establish discussions on a mechanism to facilitate the delivery of goods and humanitarian aid to Iran.