Hassan Rouhani's remarks were seen as part of his efforts to defuse claims by conservative groups that he has given too many concessions to the West in return for too little.

“Without a doubt, nuclear power is our definite right,” he said during a ceremony in Tehran marking the 25th anniversary of the demise of Ayatollah Ruhollah Khomenei, the founder of the Islamic Revolution.

“Resorting to unity and resistance, we will defend interests of Iranian nation,” Rouhani said.

Under an interim deal in November, Iran agreed to cap some parts of its nuclear activities in return for an easing of sanctions by the West.

The next high-level talks aimed at finalizing a deal will be held later this month. Another round of expert-level nuclear talks between Iran and world powers is scheduled for Wednesday in Vienna.

Russia's United Nations Ambassador Vitaly Churkin told a news conference in New York that the talks “have been going well but not without problems.”

He called for “constructive approaches” by both sides to meet the July 20 deadline for an agreement, adding that one of his “professional ambitions” at the UN is to see the Security Council lift four rounds of sanctions imposed on Iran since 2006.

President Rouhani also said Iran would support the fight against terrorism and extremism in the region, a reference to the country's role in helping Syrian President Bashar Assad in his fight against foreign-backed militants.

“The Islamic republic of Iran helps those who fight terrorism and extremism in the region,” said Rouhani.

“Today, Iran is standard-bearer of fighting terrorism and violence in the region.”

Iran has been a key regional supporter of Assad in Syria's civil war that pits him against Western-backed rebels seeking his ouster.

BA/BA