Iran warned Wednesday that its multi-billion dollar deals for Airbus planes had been thrown into doubt by US President Donald Trump's attacks on the nuclear deal.

"Considering Mr Trump's stance on pulling out of the JCPOA (nuclear deal) we must make sure that the licences will remain valid... regardless of any decision taken by US," deputy transport minister Asghar Fakhrieh Kashan told the reformist ILNA news agency.

"As long as uncertainties are not resolved, we will not provide down payments," he said.

"Because of these negotiations, there can be delays in payments."

A specific clause in the 2015 nuclear deal -- which lifted some international sanctions in exchange for curbs to Iran's atomic programme -- opened the way for Iran to purchase planes from international suppliers.Licences were granted the following year by the US Treasury's Office of Foreign Assets Control (OFAC) for Airbus to sell 100 planes to national carrier Iran Air, which has also ordered 80 from Boeing.

The European firm requires US export licences because some of its parts are manufactured there.

On Friday, Trump threatened to walk away from the nuclear deal unless progress was made on negotiations regarding Iran's missile programme, and it is unclear if this would also lead to the OFAC licences being revoked.

"OFAC's licences are valid until December 2020 but these licences have been issued under the JCPOA," said Fakhrieh Kashan.

"In the most pessimistic case, if America wanted to pull out of the JCPOA, then it can be expected that the executive apparatus too will obey this decision."

Asked to comment by AFP, Airbus said it "keeps on working with Iran Air and the Iranian authorities on the execution of the purchase agreement in full compliance with the JCPOA and other applicable regulations."

Iran has been desperate to renew its ageing fleet of planes, but has faced financing difficulties as well as the uncertainty over sanctions.

Iran Air has so far received only three Airbus planes from its 100-plane order.