WASHINGTON — Iran offered to extend a visit by nuclear inspectors.

Ali Akbar Salehi was quoted by various media on Monday as saying that he was “optimistic” about the results of the visit this week by inspectors from the U.N.’s nuclear watchdog, the International Atomic Energy Agency, and that their three-day visit could be extended “if necessary.”

The inspectors arrived Sunday as tensions between Iran and the West are ratcheting up.

U.S.-led sanctions have intensified in the wake of an IAEA report in November that cited what it said was strong evidence of a nuclear weapons program, which Iran denies.

Iran has issued and then withdrawn threats to shut the Strait of Hormuz, through which much of the world’s oil must pass.

The United States has increased its naval presence in the region, and the Washington Post reported last week that the Pentagon is considering deploying a floating base for commando raids.