Bahrain Mirror - Reuters: Iranian Supreme Leader Ayatollah Ali Khamenei renewed his criticism of a nuclear deal signed with six world powers in a speech in Tehran on Monday, and accused the United States of failing to keep its side of the bargain.

Under the deal, which came into force in October, world powers agreed to drop crippling multilateral economic sanctions against Iran in exchange for measures designed to ensure that it cannot develop nuclear weapons. Iran's moderate president, Hassan Rouhani, promised Iranians that the end of sanctions would bring growth and jobs to their moribund economy.

Khamenei gave his blessing to the deal -- but his regular criticism of its implementation has allowed hardliners to clip Rouhani's wings as the president tries to build on parliamentary gains for his moderate allies and secure re-election next year.

"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).

In particular, Khamenei said sanctions were only being removed incrementally and that foreign companies were not yet investing in Iran.

Major European banks and investors are in fact holding back from doing business with Iran, partly because of unilateral U.S. sanctions that still remain in place, but also because of the difficulties of dealing with Iran's complex regulations, a lack of transparency within its banking system, unclear dispute resolution mechanisms, labor issues and corruption.

In particular, the launch of new contracts to attract vital investment to Iran's lifeline oil industry has been postponed several times as Rouhani's hardline rivals, with Khamenei's backing, resist any end to a "buy-back" system that prevents foreign firms booking reserves or taking equity stakes in Iranian companies.

Meanwhile, citizens' impatience with the lack of improvement in their living standards is growing.

Khamenei on Monday recommended looking inside Iran for development opportunities and ways to improve ordinary people's lives.

He also said the United States had offered to negotiate with Iran on regional issues -- the two countries share an interest in fighting the Islamic State militant group in Iraq and Syria -- but that the negative experience on the nuclear deal showed that this would be like taking a "deadly poison".