Iran and the U.S. are meeting Thursday for their third round of indirect talks as President Donald Trump seeks to delay Tehran’s nuclear program while threatening it by deploying a massive number of aircraft and warships to the Middle East.

U.S. special Mideast envoy Steve Witkoff is meeting with Iranian Foreign Minister Abbas Araghchi in an effort to convince his country to halt its enrichment of uranium, a key step to building a nuclear bomb, and curtail or stop its production of long-range missiles.

What to know:

Araghchi and Witkoff held multiple rounds of talks last year that collapsed after Israel launched its war against Iran in June. These latest talks are again being mediated by Oman, a sultanate on the eastern edge of the Arabian Peninsula that’s long served as an interlocutor between Iran and the West.Iran has maintained that it wants the talks to focus solely on nuclear issues, while the U.S. pushes to halt Iran’s enrichment of uranium entirely. But Washington’s concerns also go beyond Iran’s nuclear program to its ballistic missiles, support for proxy networks across the region and other issues.There is also uncertainty about what any military action could mean for the wider region. Tehran could retaliate against the American-allied nations of the Persian Gulf or Israel. Oil prices have risen in recent days in part due to those concerns.