Iran has vowed to continue "to test its capabilities in ballistic missiles" as US President Donald Trump dialled up the rhetoric against the Islamic Republic.

A senior adviser to Iran's Supreme Leader Ayatollah Ali Khamenei hit out at the "inexperienced" Trump administration after it officially put the country "on notice" over a ballistic missile test on Sunday (29 January).

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Trump's National Security Adviser, Michael Flynn, said Iran's action was "in defiance of UN Security Council Resolution 2231", which "calls upon Iran not to undertake any activity related to ballistic missiles designed to be capable of delivering nuclear weapons, including launches using such ballistic missile technology."

US-Iran tensions have been simmering since Trump's election. The Republican is a staunch critic of the nuclear deal with Iran which was brokered by the Obama administration.

Ali Akbar Velayati, who advises Ayatollah Ali Khamenei on foreign affairs, rejected the idea that Iran had breached the 2015 nuclear accord with world powers.

"This is not the first time that an inexperienced person has threatened Iran," CNBC quoted Velayati as saying on Thursday (2 February). "Iran is the strongest power in the region and has a lot of political, economic and military power ... America should be careful about making empty threats to Iran."

He added: "Iran will continue to test its capabilities in ballistic missiles and Iran will not ask any country for permission in defending itself."

Iranian Foreign Minister Mohammad Javad Zarif said the test was "out of the sphere of the Resolution 2231 and the nuclear deal" on Tuesday (31 January).

While Flynn would not reveal whether the US would take further action beyond a verbal warning, Trump was asked by a reporter whether a military response would be considered, to which he replied: "Nothing is off the table", according to Bloomberg.

After echoing Flynn's comments, Trump tweeted on Thursday: "Iran was on its last legs and ready to collapse until the U.S. came along and gave it a life-line in the form of the Iran Deal: $150 billion".

Trump's temporary travel ban on seven Muslim-majority nations includes Iran, who promised to take "reciprocal measures".

Iranian President hit out at Trump, calling him a political novice and said: "It will take him a long time and will cost the United States a lot, until he learns what is happening in the world".

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