US President Donald Trump was hardly dealing with the storm that followed his sudden decision to fire FBI director James Comey when The Washington Post published extremely serious allegations claiming that the novice president disclosed highly classified information to Russia's foreign minister about a planned Islamic State operation. The Washington Post's report Monday plunged the White House into another controversy just months into Trump's short tenure in office. The intelligence, shared at a meeting last week with Russian Foreign Minister Sergei Lavrov and Russian Ambassador Sergei Kislyak, was supplied by a US ally in the fight against the militant group, officials with knowledge of the situation said. The Washington Post reported that the information Trump relayed was considered so sensitive that details have been withheld from allies and tightly restricted even within the US government, officials said. The US ally had not given the United States permission to share the material with Russia, and officials said Trump's decision to do so endangered cooperation from an ally that has access to the inner workings of the Islamic State group, the Post added. “This is code-word information,” said a US official familiar with the matter, using terminology that refers to one of the highest classification levels used by American spy agencies. Trump “revealed more information to the Russian ambassador than we have shared with our own allies.” Officials said that Trump went off script and began describing details of an Islamic State terrorist threat related to the use of laptop computers on aircraft. Such information was the main reason behind a decision by US authorities to ban travellers from carrying their laptops aboard while flying out of nine Arab and Muslim countries. US officials were considering expanding such a ban to European airports, but no decision has been taken. The White House declared the allegations “false” and part of the “liberal” media's campaign against the US president after defeating his Democratic rival, Hillary Clinton, in November. “The story that came out tonight as reported is false,” H R McMaster, Trump's national security adviser, told reporters at the White House, adding that the leaders reviewed a range of common threats including to civil aviation. “At no time were intelligence sources or methods discussed. The president did not disclose any military operations that were not already publicly known... I was in the room. It didn't happen,” he said. Russia's Foreign Ministry said reports that Trump had revealed highly classified information were “fake”, according to the Interfax news agency. The White House also released a statement from Secretary of State Rex Tillerson who said the Oval Office meeting focussed on counterterrorism. Deputy National Security Adviser Dina Powell also called the Washington Post's story false. Still, the news triggered concern in Congress. The Senate's No 2 Democrat, Dick Durbin, called Trump's conduct “dangerous” and “reckless”. Bob Corker, the Republican head of the Senate Foreign Relations Committee, called the allegations “very, very troubling” if true. “Obviously, they're in a downward spiral right now and they've got to come to grips with all that's happening,” he said of the White House. The latest controversy came as Trump's administration reels from the fallout over his abrupt dismissal of Comey and amid congressional calls for an independent investigation into allegations of Russian meddling in the 2016 US election. One of the officials said the intelligence discussed by Trump in his meeting with Lavrov was classified “Top Secret” and held in a secure “compartment” to which only a handful of intelligence officials have access. After Trump's disclosure of the information, which one of the officials described as spontaneous, officials immediately called the CIA and the National Security Agency, both of which have agreements with a number of allied intelligence services around the world, and informed them what had happened. While the president has the authority to disclose even the most highly classified information at will, in this case he did so without consulting the ally that provided it, which threatens to jeopardise a long-standing intelligence sharing agreement, the US officials said. Since taking office in January, Trump has careened from controversy to controversy, complaining on the first day about news coverage of his inauguration crowds; charging his predecessor, former president Barack Obama, with wiretapping; and just last week firing the FBI director who was overseeing an investigation into potential ties between Trump's presidential campaign and the Russian government. The US leader, who favours Twitter to communicate with the outside world, even went as far as threatening Comey with releasing secretly taped conversations between the two when they met over dinner at the White House. Trump said in a television interview that Comey was keen to keep his job as FBI director. He added that he asked Comey twice whether he was personally under investigation over Russia's alleged meddling in the US elections, and that he denied that this was the case. Trump, a Republican who has called allegations of links between his campaign team and Russia a “total scam”, sharply criticised his 2016 election rival Clinton for her handling of classified information as secretary of state, when she used a private email server. The FBI concluded that no criminal charges against Clinton were warranted, but Comey said she and her colleagues had been “careless” with classified information. In his conversations with the Russian officials, Trump appeared to be boasting about his knowledge of the looming threats, telling them he was briefed on “great intel every day”, an official with knowledge of the exchange said, according to the Washington Post. Some US officials have told Reuters they have been concerned about disclosing highly classified intelligence to Trump. One official, who requested anonymity to discuss dealing with the president, said last month: “He has no filter; it's in one ear and out the mouth.” Officials expressed concern about Trump's handling of sensitive information as well as his grasp of the potential consequences. Exposure of an intelligence stream that has provided critical insight into the Islamic State group, they said, could hinder the United States' and its allies' ability to detect future threats. A former senior US official who is close to current administration officials told the Washington Post, “Trump seems to be very reckless and doesn't grasp the gravity of the things he's dealing with, especially when it comes to intelligence and national security. And it's all clouded because of this problem he has with Russia.” He did not reveal the specific intelligence-gathering method, but he described how the Islamic State was pursuing elements of a specific plot and how much harm such an attack could cause under varying circumstances. Most alarmingly, officials said, Trump revealed the city in the Islamic State's territory where the US intelligence partner detected the threat. The identification of the location was seen as particularly problematic, officials said, because Russia could use that detail to help identify the US ally or intelligence capability involved. Officials said the capability could be useful for other purposes, possibly providing intelligence on Russia's presence in Syria. Moscow would be keenly interested in identifying that source and perhaps disrupting it. “If that partner learned we'd given this to Russia without their knowledge or asking first, that is a blow to that relationship,” the US official said. One of the officials with knowledge of Trump's meeting with the Russian called the timing of the disclosure “particularly unfortunate” as the president prepares for a White House meeting Tuesday with Turkish President Recep Tayyip Erdogan, an ally in the fight against the Islamic State group. Trump's first foreign trip also begins later this week and includes a stop in Saudi Arabia, another Islamic State foe, and a 25 May NATO meeting in Brussels attended by other important US allies. He also has stops planned in Israel and the Vatican. The president's trip and latest uproar over his meeting with Russian officials come amid rumours that he might shake-up his senior staff in a bid to refocus his administration.