TEHRAN, Iran — Iran’s foreign minister said Saturday a detained Princeton graduate student will be exchanged for an Iranian scientist held by the U.S., marking a potential breakthrough between Tehran and Washington after months of tensions.

Mohammad Javad Zarif made the announcement on Twitter. The trade involves graduate student Xiyue Wang and scientist Massoud Soleimani.

“Glad that Professor Massoud Soleimani and Mr. Xiyue Wang will be joining their families shortly,” Zarif wrote. “Many thanks to all engaged, particularly the Swiss government.”

In his tweet, Zarif confirmed rumors that had been circulating for days that a deal was in the works to free Wang.

There was no immediate acknowledgment of the trade by the U.S. Lawyers involved in the cases could not be immediately reached. The State Department did not immediately respond to a request for comment.

Wang was sentenced to 10 years in prison in Iran for allegedly “infiltrating” the country and sending confidential material abroad. His family and Princeton University strongly denied the claims. Iran has detained dual Iranian nationals and those with Western ties in the past to be used as bargaining chips in negotiations.

Soleimani — who works in stem cell research, hematology and regenerative medicine – was arrested by U.S. authorities on charges he had violated trade sanctions by trying to have biological material brought to Iran. He and his lawyers maintain his innocence, saying he seized on a former student’s plans to travel from the U.S. to Iran in September 2016 as a chance to get recombinant proteins used in his research for a fraction of the price he’d pay at home.

Tensions have been high between Iran and the U.S. since President Donald Trump unilaterally withdrew America from Tehran’s nuclear deal with world powers in May 2018. In the time since, the U.S. has imposed harsh sanctions on Iran’s economy. There also have been a series of attacks across the Mideast that the U.S. blames on Iran.