US President Donald Trump tweeted on Sunday that if Tehran “wants to fight”, it will be the “official end of Iran”.Trump’s stern warning added Iran should “never threaten the United States again”. His tweet comes as tensions continue to rise in the Middle East as the US and Iran come to blows over the Iranian regime’s activities, which the Trump administration sees as a direct threat to US interests in the region.Iran’s foreign minister downplayed the prospect of a new war in the region on Saturday, saying Tehran opposed it and no party was under the “illusion” the Islamic republic could be confronted. “We are certain… there will not be a war since neither we want a war nor does anyone have the illusion they can confront Iran in the region,” Mohammad Javad Zarif told state-run IRNA at the end of a visit to China.Iran-US relations hit a new low last year after Trump pulled out of a 2015 nuclear deal and reimposed unilateral sanctions on Tehran. Meanwhile, Iran urged the United States on Monday to address the Islamic republic with respect, not threats of war, a day after Trump stoked concerns about a potential US-Iran conflict.But in a sign of brewing confrontation a year after Washington quit world powers’ 2015 nuclear deal with Iran and reimposed sanctions on it, Tehran announced a fourfold increase in its rate of low-grade uranium enrichment. Tensions between Washington and its Gulf Arab allies on one side and Tehran and its Shia proxies in the region on the other have been flaring for weeks.In response to Trump’s tweet, Iranian Foreign Minister Mohammad Javad Zarif replied on his twitter account “NeverThreatenAnIranian. Try respect – it works!” Zarif, who was educated in the United States, actually praised Trump for earlier remarks seen as cautioning hawks in his administration who were encouraging conflict.The president “rightly deplores ‘military-industrial complex’ pushing U.S. #ForeverWars,” Zarif wrote on Twitter.But he said Trump had allowed a “B-team” of aides led by National Security Advisor John Bolton to “trash diplomacy”. He accused them of “milking despotic butchers via massive arms sales”, an apparent reference to Iran’s main regional foe, Saudi Arabia, Washington’s biggest arms buyer.Trump has tightened economic sanctions against Iran, and his administration says it has built up the US military presence in the region. It accuses Iran of posing threats to US troops and interests. Tehran has denied this, describing US moves as “psychological warfare” and a “political game”. Britain told Iran on Monday not to underestimate the resolve of the United States, warning that if American interests were attacked then the Trump administration would retaliate.