WASHINGTON (Reuters) - President Donald Trump told reporters on Thursday (Feb 2) said "nothing is off the table" in terms of a response to Iran's ballistic missile test.

Trump made the comment in response to a question about whether he would consider military options to respond to Iran, a day after his national security adviser put Teheran on "notice."

Trump plans to impose sanctions on several Iranian entities, seeking to ratchet up pressure on Teheran while crafting a broader strategy to counter what he sees as its destabilizing behaviour, people familiar with the matter said on Thursday.

Iran's decision to test-fire a ballistic missile on Sunday helped trigger Trump's decision, which could be announced as early as Friday, they said.

Trump later tweeted early on Friday that "Iran is playing with fire" and"they don't appreciate how kind President Obama was to them. Not me!"

In response, Iran's Foreign Minister Mohammad Javad Zarif tweeted on Friday that the Islamic Republic was unmoved by US threats following its missile test launch and that Teheran 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 defence," Zarif wrote.

"We will never use our weapons against anyone, except in self-defence. Let us see if any of those who complain can make the same statement," he tweeted.