Iran's parliament yesterday declared its dissatisfaction with President Hassan Rouhani, voting to reject his answers after grilling him over the deteriorating economy.

It was the first time Rouhani had been summoned by parliament in his five years in power, and MPs demanded answers on unemployment, rising prices and the sharp depreciation of the rial, which has lost more than half of its value since April.

The lawmakers, who have already impeached his labour and economy ministers this month, were unimpressed.

In votes at the end of the session, they expressed dissatisfaction with Rouhani's responses to four of their five questions on the economy, which will now be referred to the judiciary for review.

The economy has been battered by the return of US sanctions following President Donald Trump's decision to withdraw from the landmark nuclear deal between Iran and world powers.

Rouhani trod a difficult line, seeking to acknowledge the problems facing ordinary Iranians without admitting to a full-blown crisis.

"It should not be said we are facing a crisis. There is no crisis. If we say there is, it will become a problem for society and then a threat," he told parliament.

As usual, Rouhani offered no concrete policy proposals, instead saying the answer lay in showing a united front.

"You may talk about employment, foreign currency, recession, smuggling... I think the problem is in people's view of the future," he said.

"The people are not afraid of the United States, they are afraid of our disagreements. If the people see we are united, they will realise the problems will be resolved."

But Rouhani's government -- which staked everything on its bid to attract foreign investment through a more "moderate" approach to relations with the West -- has been badly weakened by the return of sanctions.

Most foreign firms have abandoned investment projects in Iran, and the next phase of renewed US sanctions in November will hit the crucial oil sector.

"We will not allow a bunch of anti-Iranians who have gathered in the White House to conspire against us," Rouhani vowed.

Meanwhile, The US told UN judges yesterday they had no jurisdiction to rule on Tehran's demand for them to order the suspension of debilitating nuclear-related sanctions against Iran.