DUBAI/BEIRUT - Iran's Supreme Leader Ayatollah Ali Khamenei accused the United States on Saturday of using economic pressure and ‘bullying’ to try to turn his countrymen against Islamic rule, underscoring his long-held mistrust of Tehran's main negotiating partner in nuclear talks.

Amid shouts of 'Death to America', Khamenei, who has the last word on all matters of state, reiterated in a speech in northeastern Iran that Tehran would not be pressured into giving in to Western demands in the negotiations with major powers.

But the 75-year-old cleric also voiced support for the government of President Hassan Rouhani, which is conducting the negotiations, and urged any Iranians critical of its performance not to use insults, an apparent indication that the Supreme Leader continues to place confidence in Rouhani's team. Iran, which rejects suspicions it wants to build a nuclear weapon, is negotiating with six world powers in search of a framework deal by the end of March and a final agreement by June 30.

Tehran wants a lifting of international sanctions, while the six powers are pressing for curbs on Iran's most sensitive nuclear activities for at least 10 years. U.S. Secretary of State said on Saturday that talks with Iran had made genuine progress and the time had come to make hard decisions.

Khamenei denounced the sanctions and ‘arrogant’ Western powers, blaming them and regional players for the halving of oil prices since last June, which has further squeezed Iran's economy. A man in the audience shouted ‘Death to America‘, a cry taken up by the crowd.

Khamenei continued: ‘Of course yes, death to America, because America is the original source of this pressure. They insist on putting pressure on our dear people's economy. What is their goal? Their goal is to put the people against the system.’ Khamenei challenged a message to Iranians by President Barack Obama on Thursday in which the U.S. leader said the nuclear talks represented the best opportunity in decades to pursue a different relationship between the two countries.

He dismissed Obama's assertion that there were people in Iran who stood against a diplomatic solution to the nuclear issue. ‘This is a lie. There is no one in Iran who doesn't want the nuclear issue to be resolved, and resolved through negotiations. What the Iranian people don't want is imposition and bullying from America,’ he said.

‘The other side says 'Let's come and negotiate and you accept every detail of what we say.' Neither our leaders nor our negotiating team nor the people of Iran, who are behind them, will accept this.’ Khamenei added Iran was negotiating solely on the nuclear dispute and not about regional matters, an apparent reference to conflicts and instability in Iraq, Syriaand the Gulf.

‘The goals of America on regional issues are the complete opposite of our goals. We want peace and security in the region. The politics of America is to create insecurity,’ he said. Moreover, US Secretary of State John Kerry said on Saturday talks with Iran had made genuine progress and the time had come to make hard decisions in reaching a deal to curb Tehran's nuclear programme.

Iranian President Hassan Rouhani was quoted by state news agency IRNA as saying there was ‘nothing that cannot be resolved’ between the parties, who seek a deal by the end of June. ‘In this round of talks, shared points of view emerged in some of the areas where there had been a difference of opinion, which can be a foundation for a final agreement,’ Rouhani said.

Speaking after week-long negotiations with Iran in the Swiss city of Lausanne, Kerry said he would meet European counterparts in London to try to resolve remaining sticking points. He said talks will resume next week to see whether a deal was possible.

‘We are not rushing but we recognise that fundamental decisions have to be made now and they don't get any easier as time goes by,’ Kerry said. ‘It is time to make hard decisions. The West suspects Iran of seeking the ability to produce nuclear weapons and the United Nations has imposed stringent economic sanctions on Tehran; Iransays its programme is intended only for peaceful purposes, such as medical technology and nuclear energy, and wants the swift lifting of sanctions.

The talks, called to solve a dispute that has at times threatened to push the Middle East to the brink of war, are set to resume on Thursday. Israel, which views the Iranian nuclear programme as an existential threat, views them with suspicion, fearing a deal allowing Tehran to retain nuclear potential.

‘We have not yet reached the finish line but make no mistake we have the opportunity to try to get this right,’ Kerry said. ‘It is a matter of political will and tough decision making. Kerry said the P5+1 group - the United States, Britain, France, Germany, Russi and China - would coordinate to reach an understanding on the major issues. As talks between Kerry and his Iranian counterpart broke on Friday after a week of negotiations, the sides appeared deadlocked over sensitive atomic research and lifting of sanctions. ‘The stakes are high and the issues are complicated, highly technical, and all inter-related,’ Kerry said. French Foreign Minister Laurent Fabius said his country wanted an agreement that was sufficiently robust to guarantee Tehran could not acquire an atomic bomb.

France has been demanding more stringent restrictions on the Iranians under any deal than the other Western delegations and at one point during the talks Fabius phoned his team to ensure it made no more concessions, officials said.

U.S. officials privately bristle at France's outspoken criticism of aspects of the talks and against Washington's strategy. Officials have expressed concerns that the French might block a deal. ‘France wants an agreement, but a robust one that really guarantees that Iran can have access to civilian nuclear power, but not the atomic bomb,’ Fabius toldEurope 1 radio on Saturday.

While the talks have made progress over the past year, differences are still wide enough to potentially prevent a final deal by the end of June. There was no breakthrough this week. Disagreements arose among the powers, with France insisting on a longer period of restrictions on Iran's nuclear work. It also opposed the idea of suspending some U.N. sanctions relatively quickly if a deal is struck.