Iran criticised new US sanctions on its missile programme on Thursday, saying they would undermine a 2015 nuclear deal with world powers.
"Iran condemns the US administration's ill will in its effort to reduce the positive results of the country's implementation of JCPOA (nuclear deal) commitments by adding individuals to the list of unilateral and illegal extraterritorial sanctions," foreign ministry spokesman Bahram Ghasemi said on his Telegram channel.
The administration of US President Donald Trump chose to stick by the nuclear deal with Iran on Wednesday, renewing a waiver of nuclear-related sanctions despite his past criticism of the agreement.
But it imposed new measures to punish Iranian defence officials and a Chinese business tied to Tehran's ballistic missile programme, which it says is in breach of international law because they could carry nuclear warheads in the future.
The decision came just before a Friday presidential election in Iran, in which moderate President Hassan Rouhani is fighting for a second term against hardline cleric Ebrahim Raisi, who has called for a much tougher stance against the West.
Iran denies ever seeking nuclear weapons and Ghasemi said its missile programme is part of its "absolute and legal right to build up the country's defensive capabilities".
"The Islamic Republic of Iran will continue its missile programme with power and authority based on its plans," he said.
Ghasemi said Iran would retaliate by adding nine US individuals and companies to its own sanctions list, accusing them of "clear violations of human rights" in relation to their support for Israel or "terrorist groups" in the Middle East.
Trump threatened to tear up the nuclear deal during his campaign and has launched a review of its terms, but until then he is required to decide on renewing sanctions relief at regular intervals.
His first deadline fell this week, related to sanctions on oil purchases through the Iranian central bank -- part of a 2012 law called the National Defence Authorisation Act -- that must be waived every 120 days.
The Trump administration will have to waive more sanctions next month if it wants to stick by the nuclear deal.
US Secretary of State Rex Tillerson said in April that Iran was complying with its side of the bargain, but has described the country as the world's leading state sponsor of terrorism.
Washington has maintained a raft of other sanctions related to human rights and the missile programme that continue to stifle Iran's efforts to rebuild its foreign trade.
This has been a major issue in the Iranian election, with hardliner Raisi accusing Rouhani of making too many concessions without gaining any economic benefits.
Although oil sales have rebounded since the deal came into effect in January 2016, Iran's continued exclusion from the international banking system has prevented it from signing much needed trade and investment deals with Europe and Asia.
Rouhani, who is still seen as the frontrunner in unofficial polls, has vowed to work towards the removal of remaining sanctions and called for more time to allow the benefits of the deal to reach ordinary Iranians.