 U.S. warned Iran, you will pay a heavy price if uranium enrichment continues. U.S. and Iranian officials held indirect talks in Oman last month with Omani officials shuttling between their separate rooms to deliver messages, three sources briefed on the issue told Axios Barak-Ravid. The proximity talks, which haven't been previously reported, represent the first known indirect engagement between the U.S. and Iran in this way in several months. They took place amid growing concerns in the White House about Iran's nuclear advances. Axios reported last week that White House Middle East coordinator Brett McGurk traveled to Oman secretly on May 8 for talks with Omani officials on possible diplomatic outreach to Iran regarding its nuclear program. According to the three sources briefed on the issue, an Iranian delegation also arrived in Oman at the same time. Iran's top nuclear negotiator Ali Bagheri Khan was part of the delegation one of the sources said. McGurk and the Iranian officials didn't meet according to the sources. The two sides were in separate locations with Omani officials going between them and passing messages. According to the sources, one of the main messages from the U.S. focused on deterrence. The sources said the U.S. made it clear that Iran will pay a heavy price if it moves forward with a 90% uranium enrichment the level needed to produce a nuclear weapon. It is said that the U.S. prefers diplomacy, but is prepared to take action in full coordination with its partners and allies to ensure Iran never acquires a nuclear weapon.