President Donald Trump’s ex-national security adviser, Michael Flynn, lied to the FBI, as he pleaded guilty to making a false statement to the FBI in January.
Mr Flynn was forced to resign the following month after misleading the White House about meeting the Russian ambassador before Mr Trump took office.
The charges were brought by Special Counsel Robert Mueller, as part of his investigation into alleged Russian meddling in the 2016 US election.
He admitted to one count of knowingly making “false, fictitious and fraudulent statements”.
The former aide is the most senior member of the Trump administration so far to have been indicted by the Mueller investigation.
In October, Mr Trump’s former presidential campaign manager, Paul Manafort, was accused of conspiring to defraud the US in his dealings with Ukraine. It also emerged that another ex-aide, George Papadopoulos, had pleaded guilty to making false statements to FBI agents.
Former FBI director James Comey, whom Trump fired in May, said that the president had asked him in February to drop an investigation into Flynn’s activities – the very investigation in which Flynn had, according to the charges, lied about a month earlier.
“I hope you can see your way clear to letting this go, to letting Flynn go,” Comey quoted Trump as saying. “He is a good guy. I hope you can let this go.”