US and Iranian officials engaged in indirect talks in Oman last month, where Washington conveyed a strong warning to Tehran that it would face serious consequences if it enriched uranium up to 90-percent purity, according to a report.

Brett McGurk, the White House National Security Council’s Middle East policy coordinator, and an Iranian delegation that included Ali Bagheri-Kani, Iran’s chief nuclear negotiator, were in present Oman in early May, Axios reported on Friday, citing unnamed sources.

Instead of meeting directly, the two sides remained in separate locations, with Omani officials serving as intermediaries to facilitate the exchange of messages, the report said.

One of the main messages from the US to the Iranians focused on deterrence, with Washington making it clear that Iran would pay a “heavy price” if it chose to enrich uranium up to 90 percent, the level needed to produce a nuclear bomb.

The objective of these indirect talks was to reach an “understanding” about ways to deescalate Iran’s nuclear program, its conduct in the region, and its involvement in the conflict in Ukraine, according to the report.

This comes as efforts to revive the 2015 nuclear deal have stalled since last year. The deal offered Iran relief from international sanctions in exchange for strict but temporary curbs on its nuclear program.

The agreement unraveled after the US withdrew from it under former President Donald Trump in 2018.

Last month, Yoav Gallant, the defense minister of Iran’s arch-foe, Israel, warned that if Tehran chose to enrich uranium to 90 percent, it would be a “grave mistake” with the potential to “could ignite the region.”

Iran has denied seeking to acquire nuclear weapons and insists that it has not attempted to enrich uranium beyond 60-percent purity.