Irans supreme leader said Wednesday that any negotiations with the US would "bring nothing but material and spiritual harm," adding that Tehran must be careful to limit any dealings with some "untrustworthy" European states. The comments from Ali Khamenei were part of a seven-page statement read word-for-word on Iranian state television and heavily promoted in the run-up to its release. They also come two days after Iran marked the 40th anniversary of its 1979 revolution amid heightened tensions between Tehran and Washington. "About the United States, the resolution of any issues is not imaginable and negotiations with it will bring nothing but material and spiritual harm," Khamenei said. The supreme leader went on to describe any negotiations as an "unforgiveable mistake." He also said negotiations would be like "going on your knees before the enemy and kissing the claws of the wolf." That tone is a long way from 2015, when Khamenei approved of talks between Iran and the United States that resulted in the nuclear deal between Tehran and world powers. The deal saw Iran limit its enrichment of uranium in exchange for the lifting of economic sanctions. However, that deal came under the administration of former President Barack Obama. President Donald Trump, who campaigned on a promise of tearing up the nuclear accord, withdrew the US from the deal last May and later reimposed sanctions on Iran. Tehran has now turned to the remaining signatories of the agreement, particularly the European powers - France, Germany and Britain - to salvage the agreement. But Khamenei said: “Today, the Iranian people see some European countries as cunning and untrustworthy along with the criminal America. The government must carefully preserve its boundaries with them." "Iran must not retreat a single step from national and revolutionary values." Khamenei pointed to sanctions as a big external challenge for the country and added, in an apparent jab at President Hassan Rouhani, "weakness in management" was one of the biggest internal challenges.