Under proposals discussed in rounds of talks in April, Iran would cap enrichment at 3.67%, in line with the JCPOA, all the sources said, including three Iranian officials. Tehran is also open to granting the IAEA expanded access to its nuclear sites, the Iranian sources said.

President Donald Trump is threatening sanctions on anyone who buys Iranian oil. That warning comes after planned talks between the U.S. and Iran over Iran’s rapidly advancing nuclear program were postponed.