Speaking to reporters at a press conference in Tehran, Rouhani also criticised the ongoing Turkish offensive in northern Syria, saying it was showing "no results".

But many of the questions focused on the 2015 nuclear deal between Iran and world powers, which is increasingly under threat from US President Donald Trump who has threatened to reimpose sanctions in May unless fresh curbs are put on Iran's missile programme and regional behaviour.

"We will negotiate with no one on our weapons," Rouhani said.

"Iranian-made missiles have never been offensive and never will be. They are defensive and are not designed to carry weapons of mass destruction, since we don't have any," he said.

Rouhani reiterated that the nuclear deal, signed with six world powers, could not be renegotiated.

"The key to the problems between Tehran and Washington is in Washington's hands. They need to stop their threats and sanctions and pressure, and automatically the situation will improve and we can think about our future," Rouhani said.

"The JCPOA (nuclear deal) is not negotiable, nor can it be rewritten," he added.

"It was negotiated over 30 months before it was signed. It was approved by the UN Security Council. It is meaningless to say it can be renegotiated with the United States, the Europeans or anyone else."

UN Security Council resolution 2231, which put the nuclear deal into force internationally, "urges" Iran to curb its ballistic missile tests, but this has been interpreted differently by various parties to the pact.

The Europeans have tended to see subsequent missile tests as breaching the spirit of the deal, rather than as outright "violations" as the US has claimed.

"If the Americans had used the occasion created by the nuclear deal correctly, there could have been an opportunity for negotiations on other questions, but the Americans destroyed this opportunity," Rouhani said.

- Criticism of Turkey -

Rouhani also criticised the Turkish offensive launched against Kurdish forces in northern Syria on January 20.

"The entry of a foreign army on to the soil of another country should be done with the authorisation of that country," he said.

"On principle, this action is not justified and we would like that it ends as quickly as possible. Our Turkish friends are being killed, others are being killed, Kurds are being killed -- it is bringing no results."

Rouhani nonetheless insisted that Iran, a key supporter of Syrian President Bashar al-Assad, maintained good relations with Turkey and Russia over Syria's future. The three countries have together organised peace talks aimed at ending Syria's long civil war.

Rouhani also touched on the protests that hit Iran for a week over the new year, and pushed back against the line, normally heard from conservatives, that they were primarily directed against the dire state of the economy.

"Yes people have criticisms about the economic situation and yes they're right, but they are also criticising the social situation, foreign relations and the political situation. The people have a lot to say and we should listen to them," he said.