The deal was finalized in July of 2015 and took effect six months ago, but Iran's supreme leader, Ayatollah Ali Khamenei, said regular Iranians are still suffering.

State-run media quoted Khamenei on Monday, saying: "We signed the nuclear agreement in order to get the sanctions lifted, but this has not been the case."

"The nuclear deal, as an experience, once again proved the pointlessness of negotiating with the Americans, their bad promises and the need not to trust America's promises," Khamenei was quoted as saying by the Islamic Republic News Agency (IRNA).

As the country's supreme leader Khamenei has the final say on all national issues. He accused the US of blocking Iran's reintegration in the international economic community.

The agreement called for Iran to open itself to international inspections of its nuclear sites, and to reduce its supply of lowly enriched uranium.

In return, Western economic sanctions targeting several sectors, including the country's oil exports and banking ties, were to be lifted.

Western banks remain wary

But Iran has been limited in its ability to access international credit. Many Western banks remain wary of renewing ties with Iran as legal uncertainty remains. That is due, in part, to some sanctions remaining in place in the US.

Many have blamed the US because Washington still has not given international banks the green light to do business with Iran.

But Tehran also bears some of the blame. Major European banks and investors are, in indeed, holding back from doing business with Iran, partly because of unilateral US sanctions that remain in effect, but also because of the difficulties of dealing with Iran's complex regulations, a lack of transparency in its banking system, unclear dispute resolution mechanisms, labor issues and corruption.

A perception of the accord's failure could have political consequences inside Iran, particularly for moderate President Hassan Rowhani, who supported the deal. If Iran's economy doesn't show any gains, Rowhani risks losing his re-election bid next year. He will likely be facing his predecessor, the combative hard-line conservative Mahmoud Ahmadinejad.

Iran signed the pact, along with the United States, Britain, France, Germany, Russia and China. It ended a stand-off over Tehran's nuclear program, which many, particularly the US, saw as a long-term threat as Iran built up fissile material and moved closer towards developing a nuclear bomb.

The far-reaching deal was meant to bring Iran back into the international fold.

bik/kms (AP, dpa)