The letter, delivered to Iranian Foreign Minister Abbas Araghchi via an Emirati diplomat, proposed renewed nuclear talks between the US and Iran, while threatening Tehran with consequences should it continue pursuing its nuclear program, the report said.

The letter is described as “tough,” since it reportedly ruled out open-ended negotiations and set a time limit for the parties to reach a deal.

It is unclear whether the two-month countdown began on the day the letter was delivered, or with the start of negotiations.