Iran hit back Friday at Donald Trump's warnings on Tehran's ballistic missiles programme, accusing the US president of showing "bad faith" over the 2015 nuclear accord.

"POTUS (president of the United States) always wanted to kill" the deal, Foreign Minister Mohammad Javad Zarif tweeted. "To avoid isolation, he's trying to blame it on Iran."

He charged that Trump was showing "bad faith on top of US violating the letter & spirit" of the deal.

On Thursday, the president accused Iran of not "living up to the spirit" of the deal it struck with major powers including Washington, reiterating that he viewed it as a "horrible agreement".

"I don't think Iran is in compliance," Trump said. "I don't think they're living up to the spirit of the agreement."

The accord gave Iran relief from sanctions in exchange for accepting curbs on its ability to make material for nuclear weapons.

Last month, Trump was forced to back down from a key campaign promise to withdraw from the agreement.

Trump had described it as "the worst deal ever" and accused Tehran of continuing to back extremist groups in the Middle East.

But on July 17, the White House certified that the Islamic republic was in fact sticking to the nuclear agreement.

Still, a day later, the United States imposed new sanctions on Iran -- targeting 18 individuals and entities -- over its missile programme.

The US Treasury punished Iran again later in July after Tehran tested a satellite launch rocket. The department singled out six companies Washington said were involved in the missile programme.

Iran was also slapped with a sanctions bill targeting its missile programme and alleged human rights violations, which Trump signed into law last week.

Tehran protested that the new sanctions violated the nuclear accord.

Iran says its missile programme is for defensive purposes only. It has vowed to reciprocate US sanctions.

Parliament is due to vote next week on a bill that increases funding for Tehran's missile programme and its Quds Force, the foreign operations wing of the elite Revolutionary Guards.

Source: AFP