Donald Trump's White House signaled a tougher stance toward Iran on Wednesday, condemning a recent missile test and declaring America was putting the Islamic republic "on notice."

In his first public remarks since taking office, National Security Advisor Michael Flynn accused Barack Obama's administration of having "failed to respond adequately to Tehran's malign actions."

Flynn cited a recent missile test and the actions of Iranian-backed rebels in Yemen as examples of Tehran's malign behavior.

"Iran is now feeling emboldened," Flynn said, in trenchant pre-written remarks, "as of today, we are officially putting Iran on notice," he said without elaborating.

Both Trump and Flynn have been harsh critics of Tehran and vocal opponents of an international deal that saw Iran curb its nuclear program in return for sanctions relief.

Chris Sherwood, a Pentagon spokesman, said there had been "no change in the U.S military posture" around Iran at this time.

"We stand ready to defend America's interest and partners around the world," he said.

Flynn insisted that Sunday's missile test was "in defiance of UN Security Council Resolution 2231," which calls on Iran not to test missiles capable of delivering nuclear weapon.

Iran's ballistic missile program has been a bone of contention with the West since the nuclear deal took effect in January last year.

But a previous, while controversial, test was not found to be in breach of the UN guidelines.

It remains to be seen if the White House will push for sanctions this time around.