The measures come a day after President Trump said "nothing is off the table" in dealing with Iran.
But Iran's Foreign Minister Mohammad Javad Zarif tweeted on Friday that the Islamic Republic was unmoved by US threats.
He said Iran had no intention of using its military against any country, except in self-defence.
"Will never initiate war, but we can only rely on our own means of defence," Mr Zarif wrote.
On Thursday, a bipartisan group of more than a dozen US senators wrote to Mr Trump, urging "full enforcement of existing sanctions and the imposition of additional sanctions on Iran for its ballistic missile program".
"Iranian leaders must feel sufficient pressure to cease deeply destabilizing activities, from sponsoring terrorist groups to continued testing of ballistic missiles," the group wrote.