President Donald Trump announced Monday that the United States will hold direct talks with Iran later this week regarding its nuclear program.

The surprise announcement came during an Oval Office meeting with Israeli Prime Minister Benjamin Netanyahu.

“We are meeting very importantly on Saturday at almost the highest level, and we'll see how it works out,” Trump said.

He added, “Iran cannot have a nuclear weapon. If the talks aren't successful, I actually think it will be a very bad day for Iran.”

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Trump did not share details about the talks, including who would be involved or where they would take place.

The announcement follows Iran’s rejection of direct negotiations with the U.S. In response to a letter from President Trump, Iran’s president said the administration needed to demonstrate it could build trust before talks could take place.

During his first term, President Trump withdrew the United States from a multinational nuclear agreement signed in 2015. The deal — between Iran, the U.S., France, the U.K., Germany, Russia, and China — placed restrictions on Iran’s nuclear program in exchange for relief from economic sanctions.