With little detail available and key questions unresolved, the U.S.-Iran interim deal to end the Middle East war remained surrounded by doubt Tuesday.

U.S. President Donald Trump said on Monday that a preliminary agreement to end ⁠the conflict had been signed by the U.S. and Iran, although details ⁠have yet to be made public and both countries said a permanent truce was yet to be negotiated.

The interim agreement would extend a tenuous cease-fire announced in April by another 60 days and reopen the Strait of Hormuz, which Iran has effectively blocked since the U.S. and Israel ​attacked Iran in February.

Negotiators would address difficult issues like the future of Iran's nuclear program during the next ​phase ⁠of talks to be held during the 60-day window.

Two other issues that Trump and Israeli Prime Minister Benjamin Netanyahu used to justify the war – ending Iran's support for regional armed proxies and curbing its missile program – are not thought to be on the agenda for those negotiations.