U.S. President Donald Trump has warned in a tweet that Iran is "playing with fire," talking tough for a second day after Tehran's latest ballistic missile test.
Trump also tweeted on February 3 that the Iranian government didn't appreciate how "kind" the United States had been to them.
That was an apparent reference to the nuclear deal struck with Tehran by the United States and other world powers in 2015, under which Iran's nuclear capability was reduced in return for a loosening of sanctions.
Iran's Foreign Minister Mohammad Javad Zarif said on Twitter on February 3 that his country was unmoved by threats, and that Tehran would never initiate war.
"Iran unmoved by threats as we derive security from our people. Will never initiate war, but we can only rely on our own means of defense," Zarif's tweet said.
U.S. news media reported that the White House is preparing to impose new sanctions on Iran as early as February 3.
Up to two dozen Iranian individuals, companies, and government agencies could be penalized as part of the move, the reports said, citing anonymous U.S. officials.
The sanctions would come after Iran was "formally put on notice” by Washington on February 2 over Tehran’s recent test of a medium-range ballistic missile.
The United States says the January 29 missile launch defied a 2015 UN Security Council resolution calling on Iran not to test nuclear-capable missiles, which Tehran denies.
Trump campaigned on promises to take a much tougher stance on Iran than his predecessor, Barack Obama, in response to actions including threats against Israel and involvement in conflicts in Syria and Yemen.