US President Donald Trump on Tuesday warned Iran to end its aggression in the Middle East or face the prospect of tougher economic sanctions, but left the door open for talks as European powers sought to cool tensions. Mr Trump’s remarks to the annual United Nations General Assembly came as French President Emmanuel Macron pushed to end a summer of escalation and rhetoric between the US and Iran that has raised the chances of a military confrontation. But hours after Mr Trump spoke at the UN he was confronted by mounting domestic political pressure as Democrats announced they would begin impeachment proceedings over claims of him seeking political help from Ukraine. House Speaker Nancy Pelosi confirmed an investigation was under way, saying Mr Trump had committed “a violation of the law” and that he “must be held accountable”. Mr Trump responded by calling the launch of the inquiry “witch hunt garbage”. At the UN, France, Germany and Japan held talks separately with Mr Trump and Iran’s President Hassan Rouhani. Mr Macron led the diplomatic effort. Escorting a smiling Mr Rouhani to a meeting with British Prime Minister Boris Johnson, the French leader said time was running short. “If he leaves the country without meeting with President Trump, honestly this is a lost opportunity because he will not come back in a few months,” Mr Macron said. “And President Trump will not go to Tehran, so they have to meet now,” he said, as Mr Johnson voiced agreement. Head to head talks would be unprecedented, at odds with enmity between the two countries since an Islamic revolution in Tehran in 1979 was followed by the US embassy hostage crisis and the breaking of diplomatic relations a year later. A meeting also seemed unlikely during Mr Trump's 36-minute speech at the UN. The US president's delivery lacked the bombast of two previous appearances at the General Assembly, but Mr Trump said Iran was guilty of “violent and unprovoked aggression”. He attributed the September 14 attacks on Saudi Aramco oil facilities to Tehran and said the US sanctions that followed were the toughest yet imposed. “As long as Iran’s menacing behaviour continues, sanctions will not be lifted. They will be tightened,” he said, criticising Iranian leaders and repeating that he considers them to be the world’s leading state sponsor of terrorism. Mr Trump spoke a day after Britain, France and Germany joined the US and Gulf states in blaming Iran for the Aramco attacks, which caused disruption to global energy supply. The European decision appeared to turn up the pressure on Iranian officials to accept new conditions on the 2015 nuclear deal. Tehran recently stopped complying with the agreement in response to Mr Trump’s withdrawal from it last year. Iran's Foreign Minister Javad Zarif has conceded that the country is open to augmenting the existing nuclear deal. If the US agreed to a permanent lifting of sanctions Iran would commit to more intrusive inspections of its nuclear sites, Mr Zarif said, and a ban on atomic weapons would be enshrined in law. But Mr Trump said he stuck by his move to abandon “the terrible Iran deal”, accusing its remaining parties – Britain, China, France, Germany and Russia – of not ensuring sufficient monitoring of nuclear sites. <span><span><span>The existing agreement “has very little time remaining”, Mr Trump said. All responsible nations had a duty to act against Iran’s “fanatical quest for nuclear weapons and the means of delivering them”.</span></span></span> <span><span><span>But the US leader, who has repeatedly said he is against American troops being used in “dumb wars”, stressed he was not interested in such a confrontation with Iran.</span></span></span> <span><span><span>Nor did he believe that Iran and the US should be implacably opposed.</span></span></span> <span>“<span>Many of America’s closest friends today were once our greatest foes,” Mr Trump said.</span></span> <span>“<span>The United States has never believed in permanent enemies. We want partners, not adversaries. America knows that well anyone can make war, only the most courageous can choose peace.”</span></span> <span><span><span>Mr Macron, who last month pitched the idea of an Iran summit to Mr Trump </span>said earlier on Tuesday that the biggest risk was an “uncontrolled escalation” in the Gulf. He called for urgent talks involving countries in the region, as well as Iran and the US.</span></span> <span>“<span>Now more than ever is the time for negotiations among Iran, the United States, the signatories of the Joint Comprehensive Plan of Action and regional powers, centered on the region’s security and stability,” he said in his address to the General Assembly, using the formal name for the nuclear deal.</span></span> <span><span><span>The French leader said he had an “extremely direct” 90-minute discussion with the Iranian president on Monday evening in which he had raised the attacks in Saudi Arabia.</span></span></span> <span>“<span>We need to get back around the table to have frank and demanding discussions on Iran’s nuclear, regional and ballistic activities but also to have a broader approach than sanctions,” Mr Macron said.</span></span> <span><span><span>Mr Rouhani is to address the General Assembly on Wednesday, when Mr Trump is also expected to deliver a statement before leaving New York.</span></span></span> <span><span><span>Although Mr Trump is renowned for giving fiery speeches, his address before world leaders came off as more measured, even dull, and he highlighted domestic themes as well as his trade battle with China.</span></span></span> <span><span><span>But the pressure of the impending impeachment proceedings was also said by sources to be weighing on him.</span></span></span> <span><span><span>The allegations centre on a telephone call between Mr Trump and Ukrainian President Volodymyr Zelensky on July 25.</span></span></span> <span><span><span>A claim that the US leader breached the constitution stems from a complaint raised by a whistleblower who said Mr Trump attempted to pressure Mr Zelensky to open a corruption investigation into his main challenger for the White House, Joe Biden, and Biden’s son Hunter, who once had business interests in the country.</span></span></span>