Iran has warned the United States it will take action if an American warship returns to the Persian Gulf. It left the area when Iran started its 10-day naval war games, during which they successfully test-fired a number of different missiles. But Russia's defence ministry says that despite the latest military exercise, the Iranians don't have the technology to make intercontinental ballistic missiles. Meanwhile France is pushing for stricter sanctions as it says it's sure Tehran is developing nuclear weapons. It's urged EU countries to follow the U.S. in freezing Iranian central bank assets and imposing an embargo on oil exports. .