DUBAI - The United States is still fundamentally hostile to Iran and its policies have undermined the benefits of sanctions relief, the Islamic Republic's hardline leader said on Sunday, warning Iranians not to trust their old enemy.Ringing in a new Iranian year at a televised rally in the Shi'ite holy city of Mashhad, Supreme Leader Ayatollah Ali Khamenei said fear of US regulations was keeping big foreign companies, particularly in the financial sector, away from Iran.The uncompromising stance of Iran's most senior figure poses a challenge to President Hassan Rouhani, the architect of last year's nuclear deal who hopes to open Iran's economy to the world.In keeping with the deal, many international sanctions on Iran were lifted in January. Since then foreign business delegations have flocked to Tehran and billions of dollars of deals have been signed.But European banks and other companies have stayed away, largely due to remaining US sanctions. That, Khamenei said, was a sign that Iran should be economically self-reliant because the US and its allies were not reliable partners."In Western countries and places which are under US influence, our banking transactions and the repatriation of our funds from their banks face problems ... because (banks) fear the Americans," he said."The US Treasury ... acts in such a way that big corporations, big institutions and big banks do not dare to come and deal with Iran," Khamenei said. The Central Bank of Iran has also said remaining US sanctions have scared off European firms. To drive the point home, the stage on which Khamenei sat carried a giant banner reading "the year of the Resistance Economy: Action and Implementation," his chosen slogan for the Iranian year 1395 that began on Sunday.DIFFERENT VIEWSIn a video message earlier, Rouhani said further engagement with other countries was the key to economic growth, a view that has put him increasingly at odds with Khamenei, who outranks him."I am sure that with cooperation and effort inside the country, and constructive engagement with the world, our economy can bloom and develop," Rouhani said.The president's allies made gains in parliamentary elections last month that could help him push through reforms in support of a more open economy. But Khamenei and his conservative allies have the power to block new legislation.Khamenei, a 76-year-old cleric, also urged the young men in the crowd not to forget Iran's revolutionary history, which he said was proof that the Islamic Republic could stand on its own and that foreign powers were not to be trusted.He saw evidence of institutional hostility towards Iran in the US presidential election, saying the candidates had "competed to vilify Iran in their speeches."He also said the United States had no business trying to stop Iran developing its defensive capabilities, including missiles, or carrying out military drills. "America is thousands of kilometers away from the Persian Gulf and conducts exercises there with regional countries ... but if we have exercises in our own security realm they protest loudly," he said.