Ex-national security adviser Michael Flynn has pleaded guilty to making false statements to the FBI about meetings with Russia’s ambassador weeks before Donald Trump became president.
The charges were brought by Special Counsel Robert Mueller, as part of his inquiry into alleged Russian meddling in the 2016 US election.
Mr Flynn is the most senior member of the administration to be indicted.
He also revealed he was co-operating with Mr Mueller’s inquiry.
Significantly, a statement made by Mr Flynn to prosecutors appears to implicate a more senior, though unnamed, Trump team official – indicating the direction in which Mr Mueller’s investigation may be heading.
Numerous US media outlets said the senior official now under the spotlight is Jared Kushner – Mr Trump’s adviser and son-in-law.