Washington told the United Nations that the airstrikes hit facilities used by militia blamed for an escalating series of drone and rocket attacks against US forces in Iraq.
Blinken reiterated support for returning to the nuclear accord, with which UN inspectors said Iran was complying before Trump pulled out the United States.
But only a handful will be allowed to run after vetting by the Guardian Council, a conservative-dominated, unelected body in charge of overseeing elections.
The goal is to find a way back to the accord known by its acronym JCPOA, which former US president Donald Trump walked away from and which his successor Joe Biden wants to revive.
The Guards said its navy was conducting "routine missions in the territorial waters" of Iran, but did not specify whether the American vessels had entered the Islamic republic's waters.