The Trump administration had announced earlier Friday that the Treasury Department would place new economic sanctions on Iran after the country tested a ballistic missile.
"The sanctions today I think are going to be very, very strong and impactful," Spicer told reporters. "And I hope that Iran realizes that after the provocative measures that they've taken, that they understand that this President, this administration, is not going to sit back, take it lightly."
Earlier in the briefing, Spicer suggested leaving all options on the table was Trump's deliberate strategy to keep adversaries guessing.
"I think one of the things that the President has said throughout the campaign, during the transition, and since becoming President is he doesn't like to telegraph his options," he said. "That's how he believes that you can have a much greater successful option."