US B-1 bombers took off from a British airbase on Tuesday for what Washington described as the “most intense” wave of airstrikes yet on Iran, hours after US secretary of war Pete Hegseth said the campaign would reach “its most ferocious day” since the conflict began.The escalation comes as the US and Israel intensify military pressure on Tehran in the ongoing conflict, even as Iranian leaders vow to continue fighting.The sorties were launched shortly after Hegseth’s declaration that US forces would unleash “sustained operations” across Iranian military and missile sites. The airstrikes shook parts of Tehran overnight, with residents describing extended bombardments and widespread electricity outages.The use of a UK base follows initial hesitation from London over Washington’s request to operate from British territory. Prime Minister Keir Starmer later said the facilities could be used for strikes linked specifically to Iran’s missile programme, though not for other targets in the conflict.As the military pressure mounts, Israel’s Prime Minister Benjamin Netanyahu said the broader objective of the war is the overthrow of Iran’s government, declaring that “we are breaking their bones.”Iran’s leadership, however, has rejected any suggestion of backing down.Iran’s parliamentary speaker, Mohammad Bagher Qalibaf, dismissed talk of a ceasefire, while senior security official Ali Larijani issued a warning to US President Donald Trump on X.“Iran doesn’t fear your empty threats. Even those bigger than you couldn’t eliminate Iran. Be careful not to get eliminated yourself,” he said in a snarky remark directed to Trump.Meanwhile, residents in Tehran reported some of the heaviest airstrikes since the conflict began overnight, with several neighbourhoods experiencing power cuts. One resident said the ground shook for nearly half an hour around midnight due to nearby strikes, while another said he feared he might not survive the night.The fighting has also heightened global economic concerns. The International Energy Agency convened an emergency meeting of its 30 member states in Paris to assess risks to oil supply and consider whether to release emergency reserves, warning that the Middle East situation is creating “significant and growing risks” for the oil market.Despite the escalating attacks, political divisions remain in Washington over the war’s direction. Democratic Senator Mark Kelly said the Trump administration appears to lack a clear objective or timeline.“Clearly, they do not have a strategic goal,” he said. “They didn’t have a plan. They have no timeline. And because of that, they have no exit strategy,” Kelly said.