Iran's President Hassan Rouhani warned Tuesday to exit the 2015 nuclear deal with world powers if the U.S. keeps on imposing new sanctions, he said in a televised address.

Rouhani's comments come with the nuclear deal under mounting pressure after Tehran carried out missile tests, and Washington imposed new sanctions -- with each accusing the other of violating the spirit of the agreement.

Rouhani warned that Iran was ready to exit the 2015 deal, which saw the lifting of most international sanctions in return for curbs on its nuclear programme, if Washington persisted.

He said Iran did prefer to stick with the nuclear deal, which he called "a model of victory for peace and diplomacy over war and unilateralism" but that this was not the "only option".

Rouhani said Trump had shown he was an unreliable partner not just for Iran but for the U.S. allies.

Iran's parliament on Sunday approved more than half a billion dollars in funding for the country's missile programme and foreign operations of the elite Revolutionary Guards in response to the new U.S. sanctions.