WASHINGTON — Iran said Monday that it had begun running a significant number of new, advanced uranium centrifuges, accelerating its ability to produce enough nuclear material to make a bomb and throwing its 2015 nuclear deal with world powers into further disarray.

The big question now is how quickly Iran, with its new capacity, could produce the fuel needed for a single bomb. Some analysts say that it might be able to do so in under a year.

The announcement was Tehran’s third move in six months to ratchet up pressure on the West in response to President Trump's decision to exit the nuclear agreement and reimpose sanctions on Iran.

It came the same day that the White House imposed a new set of sanctions aimed directly at top aides to Ayatollah Ali Khamenei, the nation’s supreme leader. The sanctions were timed to mark the 40th anniversary of the American Embassy takeover in Tehran.