Sources said Trump, angry that outgoing Attorney General William Barr didn't publicly announce the ongoing investigation into Hunter Biden, has discussed the matter with allies.

Hunter Biden's ties to Burisma in particular have long dogged the policy work and political aspirations of his father, Joe Biden, now the president-elect of the United States.

In a statement released by the president-elect's transition office, Hunter Biden said he learned about the investigation on Tuesday.

Twitter is changing its policy on hacked content after an outcry about its handling of a New York Post story prompted cries of censorship.

Donald Trump and his campaign have seized on a New York Post article, which is being limited on Twitter and Facebook, angering conservatives.

The chairman of the U.S. House Foreign Affairs Committee said the panel will prepare a contempt resolution because of what he called Pompeo's "unprecedented record of obstruction and defiance of the House's constitutional oversight authority.''

There is no evidence of wrongdoing by the Bidens, and Hunter Biden has denied using his influence with his father to aid Burisma.

The findings from the House Judiciary Committee do not spell out the formal charges against the president, which are being drafted ahead of votes, possibly as soon as next week.

Two top national security aides who listened to U.S. President Donald Trump’s call with Ukraine are preparing to testify in the impeachment hearings, launching a week of back-to-back sessions as Americans hear from those closest to the White House.

The witnesses for the committee's hearings on Tuesday, Wednesday and Thursday next week have already given closed-door depositions, Schiff, a Democrat, said in a statement.