Iran has rejected a warning from US President Donald Trump's administration over its latest missile test as unfounded.
Bahram Ghasemi, the Iranian foreign ministry spokesman, was quoted as saying on Thursday by state news agency IRNA that the claims were "baseless, repetitive and provocative".
"Instead of thanking Iran for its continued fight against terrorism ... the American government is practically helping the terrorists by claims about Iran that are baseless, repetitive and provocative," he said.
Also on Thursday, a top adviser to Supreme Leader Ayatollah Ali Khamenei said Iran would not yield to "useless" US threats from "an inexperienced person" over its ballistic missile programme.
"This is not the first time that an inexperienced person has threatened Iran ... the American government will understand that threatening Iran is useless," Ali Akbar Velayati said, without identifying any US official specifically in his comments.
"Iran does not need permission from any country to defend itself," he was quoted as saying by the semi-official Fars news agency.
President Donald Trump himself tweeted earlier on Thursday that the Islamic republic was now formally "on notice" after Sunday's missile test.
"Iran has been formally PUT ON NOTICE for firing a ballistic missile. Should have been thankful for the terrible deal the US made with them!" Trump tweeted, echoing similar comments by National Security Adviser Michael Flynn on Wednesday.
Later on Thursday, responding to a question about whether he would consider military options to respond to Iran, Trump told reporters "nothing is off the table".
The White House said Iran's action would not go "unresponded to".
"We will have further updates for you on those additional actions, but clearly (national security adviser Michael Flynn) warned to make sure that Iran understood that they are on notice that this is not going unresponded to," said Sean Spicer, the White House spokesman.
The nuclear deal
Trump was referring to the nuclear accord between Tehran and world powers that took effect in January 2016, lifting international sanctions in return for curbs on Iran's atomic programme.
Flynn insisted that the missile test was "in defiance of UN Security Council Resolution 2231", which calls on Iran not to test missiles capable of delivering a nuclear weapon.
Iran confirmed on Wednesday that it had tested a ballistic missile, but denied that it had violated the terms of the nuclear deal.
Tehran has said its missiles do not breach UN resolutions because they are for defence purposes only and are not designed to carry nuclear warheads.
Source: News agencies