Robert Mueller, the official who led an investigation into alleged Russian interference in the 2016 US election, is to testify before Congress.
He will face questions at two lengthy hearings, with the first set to begin at 08:30 local time (12:30 GMT).
Mr Mueller has been reluctant to testify, but agreed to do so after two committees issued subpoenas.
His testimony comes three months after he released his findings on Donald Trump’s campaign and Russia. Read more