President Hassan Rouhani defended a potential nuclear deal with the West on Tuesday, insisting that an agreement would benefit the majority of Iranians, while encountering resistance.

In a primetime interview lasting 90 minutes, Rouhani, who is under growing pressure from hardliners and hard-pressed citizens, stood by the steps taken to ensure removal of sanctions imposed on Iran over its nuclear ambitions.

He also said that relations with the United States, marked by decades of hostility, "have been and will be difficult," but it was possible that "tensions with all countries can be reduced."

"The people are very happy about the sanctions being lifted," Rouhani said on state television, referring to last November's interim deal that won Iran modest relief and ensured the release of billions of dollars from frozen overseas accounts.

Sanctions have crippled Iran's economy, which remains in recession, but the president condemned those who profited from the restrictions while ordinary citizens suffered.

- Under attack -

"A small, fringe group is very angry about it because they will suffer losses," under a nuclear deal, Rouhani said.

He referred to the case of Babak Zanjani, a tycoon who helped the previous government of president Mahmoud Ahmadinejad circumvent sanctions, saying he pocketed $3 billion.

Rouhani's administration is increasingly coming under attack from ultra conservative camps, particularly over the nuclear negotiations with world powers.

A self-declared moderate who was elected last June on a promise to improve the economy, Rouhani's reforms -- mostly designed to rein in inflation -- are testing his popularity.

He encountered a backlash last week after it was announced that prices of government-subsidised fuel, utilities and basic foods would rise.

Earlier Tuesday he derided hardliners critical of his style of governance and outreach to the West, saying they do not speak for the country.

"I am proud that the government has created a situation allowing everyone to easily talk and criticise -- even though sometimes (they) make a mountain out of a molehill," he said, while insisting those voicing criticism must reveal their political identities and not hide under "the Iranian nation" mantra.

"They should say who they are and whom they are aligned with," he said, adding that Iranians were seeking "moderation, tranquility and progress."

To achieve those goals which he says were set by the people electing him as president, Rouhani says the economy must be fixed and Iran must repair its tarnished relations with the world.

He has rallied domestic support -- including the essential backing of Iran's top authority and supreme leader Ayatollah Ali Khamenei -- to engage world powers over the Islamic republic's nuclear ambitions and seek an end to sanctions.

But hardliners are opposed to any compromise on Iran's nuclear work, which the West suspects masks military objectives though Tehran insists is purely for peaceful purposes.

Rouhani's political opponents have been particularly critical of the interim agreement, arguing that the concessions Iran made -- curbing and freezing some parts of its nuclear drive -- outweigh its gains.

Iran and the so-called P5+1 group of the United States, Britain, France, China and Russia plus Germany are now seeking a permanent accord against a July 20 deadline.

- 'I am Rouhani' -

Rouhani's domestic policy -- wherein he has promised greater social freedoms -- is also a target for censure, with many religious figures warning of creeping Western culture targeting Iran's Islamic and revolutionary values.

But some moderates and pro-reformists are also unhappy, saying social change is not being implemented fast enough.

Rouhani's remarks on Tuesday come amid controversy over a film claiming to document his political career and revolutionary credentials before he assumed Iran's highest-elected office.

Recalling actions Rouhani made in the 1980s and 1990s as a lawmaker, a top security official and as Iran's top nuclear negotiator, the movie -- called "I Am Rouhani" -- depicts him as a figure who transformed from a hardline revolutionary to a pragmatic technocrat leaning towards the West.

Rouhani's office has criticised the film and said "some parts are incorrect," without further elaboration.

Considered as an establishment insider since the 1979 Islamic revolution, Rouhani also represented Khamenei in the country's powerful Supreme National Security Council.