Iranian Supreme Leader Ali Khamenei said on Sunday that if the United States starts a war against Iran, it will be regional.

He made the remarks at a meeting in Tehran as tensions remain high between the two countries.

Khamenei said that Iran would not start a war and does not seek to attack any country, "but the Iranian people will deliver a hard punch to those seeking to attack and harass them".

"The Americans should know that if a war is launched, this time, it will be a regional war," he emphasised.

US President Donald Trump has said that a "massive armada", led by the aircraft carrier Abraham Lincoln, is heading towards Iran, warning that "time is running out" for Tehran to reach a deal with the United States.

In response, Iran's foreign minister said, "our brave armed forces are prepared ... to immediately and powerfully respond to any aggression". (Xinhua)