ANKARA: Iran will abandon its nuclear agreement with world powers if it failed to serve the country?s national interests, President Hassan Rouhani said in a harsh reaction to Donald Trump?s decision not to certify the 2015 accord.

Trump said in an address at the White House that he would not continue to certify the multinational agreement and warned he might ultimately terminate it.

Growing strains with the United States will intensify a power struggle among Iran?s faction-ridden elite by boosting Rouhani?s anti-Western hard-line rivals who feared losing power if the deal ended the country?s political and economic isolation.

?No president can revoke an international deal. ... Iran will continue to honour its commitments under the deal,? Rouhani said in a live television address, saying Trump?s speech had nothing new but ?fake accusations and insults? against Iranians.

?However, if one day our interests are not served, we will not hesitate even one moment and will respond.?

While Trump did not pull the United States out of the agreement, aimed at preventing Iran from developing a nuclear bomb, he gave the US Congress 60 days to decide whether to reimpose economic sanctions on Tehran that were lifted in 2016.

That increases tension with Iran as well as putting Washington at odds with other signatories of the accord such as Britain, France, Germany, Russia, China and the European Union, who say the United States cannot unilaterally cancel the 2015 nuclear deal between Iran and world powers.

?The agreement will remain intact and no article or paragraph would be added or taken away from it, ... The nuclear deal cannot be renegotiated,? Rouhani said.

Iranian Supreme Leader Ayatollah Ali Khamenei, the highest authority in the Islamic Republic, has warned Washington over any ?wrong move,? saying Iran would stop implementing it if any sanctions were reimposed.

EXPANDING MISSILE WORK

In his speech, Trump also detailed a more confrontational approach to Iran over its ballistic missile programme and its support for extremist groups in the Middle East.

The United States has imposed unilateral sanctions on Tehran over its ballistic missile tests for what it said was in violation of a U.N. resolution that endorsed the nuclear deal.

?The Iranian nation has not and will never bow to any foreign pressure... our missiles are for our defence. ... We will double our efforts from now to expand our defence capabilities,? Rouhani said.

Trump also announced plans to take action against Iran?s Islamic Revolutionary Guard Corps (IRGC), which he said was Khamenei?s ?corrupt personal terror force and militia.?

Defying Trump, Iran?s pragmatist Rouhani backed the IRGC , saying the elite force will continue its fight against ?regional terrorists.?

?The IRGC has always protected our nation against terrorists. ... It will continue to help oppressed nations in the region,? Rouhani said.

The IRGC is Iran?s most powerful security entity and wields control over large swathes of Iran?s economy as well as considerable influence within its political system.

The escalating regional tensions will increase the nervousness of potential foreign investors, many of whom were already keeping Iranian ambitions on hold due to worries about remaining unilateral US sanctions or a possible restoration of sanctions.