US President Donald Trump has ordered US intelligence agencies to cooperate in an investigation into whether he was spied in the 201
The investigation, led by Attorney General William Barr, examines the origins of Russia's investigation.
It has long been demanded by Mr. Trump, who often calls the investigation of Russian interference "witch hunt".
On Thursday, he announced a policy that gave Mr Barr new powers, including the release of documents.
Mr. Barr is already being scrutinized and criticized by Democrats – accusing him of acting on behalf of the President and not in the national interest.
What is the new investigation?
The President has repeatedly suggested his campaign was spied on, accusing intelligence agencies of abusing their power.
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He also said that this could mean "betrayal" and suggested those involved should be prosecuted.
In April, the Attorney General shared with Congress that "espionage" on the Trump campaign occurred and said he wanted to make sure that any news gathering was legitimate.
Earlier this month, Mr. Barr assigned a federal prosecutor to deal with the origins of the Russia investigation. Mr. Trump refused to ask Mr. Barr to do so.
Thursday's letter of intent instructs the head of intelligence services to provide Mr. Barr with "immediate" information at his request.
Today's action will help all Americans learn the truth "about the events and measures taken during the last presidential election and restore confidence in our public institutions," spokeswoman Sarah Sanders said in a statement.
What did the Russia investigation find out?
After nearly two years, a revised version of the report prepared by Special Adviser Robert Muller was published in April.
The report concluded that Russia interfered in the presidential elections of 2016 "flat-rate and systematic", but had not realized this. It constituted a criminal plot between them and the Trump campaign.
However, it did 10 cases in which Mr Trump may have attempted to obstruct the investigation.
According to the reporter After his release, Mr. Barr was accused of having wrongly characterized his findings in a previously published abstract.
He has not since appeared before the Judiciary Committee of the House and was scorned for ignoring them. They presented an unedited version of the report.
Mr. Müller himself said he was "frustrated" by Mr. Barr's summary and said it lacks the context.
How did Democrats react?
The chairman of the House Intelligence Committee is among those who have criticized the expanded statement of power.
"Trump and Barr conspire to bring prosecution and classified information against their political enemies," Adam Schiff said on Twitter.
"The cover-up has entered a new and dangerous phase, which is un-American," he added.
This comes at a time of high tensions between senior Democrats and President Trump.
He and House Speaker Nancy Pelosi bickered on Thursday about the other's mental stability after Mr. Trump abruptly stopped meeting earlier this week.
Mr. Trump has announced the end of all bipartisan cooperation with the Democrats until they have stopped all investigations against him.
Mr. Barr himself is under intense scrutiny and criticism. He was charged with acting on behalf of the President and not in the national interest.
Ms. Pelosi has accused Mr. Barr of committing a crime by lying to Congress during a hearing on the report – an allegation he dismissed as "ridiculous".