The US Attorney General Jeff Sessions has suggested that arresting WikiLeaks founder Julian Assange is a 'priority' for the US.
Mr Assange, who is wanted in Sweden for questioning over a rape allegation, has been living in the Ecuadorian Embassy in London since 2012.
He was granted political asylum by Ecuador amid fears he would be extradited to the United States if he is arrested by Swedish officials.
He is expected to be arrested by British police and sent to Sweden if he leaves the embassy. He was interviewed by Swedish prosecutors over the allegation - which he denies - last year.
Mr Assange - whose organisation has published confidential documents relating to the US intelligence services - is the subject of a "very serious criminal investigation" in the US, officials have previously admitted.
The Justice4Assange group has claimed the investigation "virtually assures that he will be indicted", although there has previously been no public indication of formal charges or extradition requests from the US.
However, Mr Sessions has now acknowledged efforts to arrest the WikiLeaks founder.
When asked by reporters if arresting Mr Assange was a priority for US justice officials, he said: "We are going to step up our effort - and already are stepping up our efforts - on all leaks. This is a matter that has gone beyond anything that I'm aware of.
"We have professionals [...] that are shocked by the number of leaks, and some of them are quite serious. So yes it is a priority... whenever a case can be made, we will seek to put some people in jail."
CNN, citing unnamed sources, reported that US officials have 'prepared charges' against Mr Assange.
WikiLeaks repeatedly made headlines during last year's US election campaign, as it published huge archives of leaked emails linked to Hillary Clinton's campaign.
Donald Trump praised the group during the campaign, once telling supporters "I love WikiLeaks". However, his administration has since taken a hardline on leaking.
The real story here is why are there so many illegal leaks coming out of Washington? Will these leaks be happening as I deal on N.Korea etc?
— Donald J. Trump (@realDonaldTrump) February 14, 2017
CIA director Mike Pompeo has accused WikiLeaks of 'walking like a hostile intelligence service and talking like a hostile intelligence service'.
In a speech earlier this month, he argued: "It is time to call out WikiLeaks for what it really is – a non-state hostile intelligence service often abetted by state actors like Russia [...] Assange claims to harbor an overwhelming admiration for both America and the idea of America. But I assure you that this man knows nothing of America and our ideals."
Mr Assange took to Twitter this morning to criticise the Trump administration:
Trump promised to 'drain the swamp' not to feed the First Amendment to its most bloated monster. pic.twitter.com/7B4aPuGFsj
— Julian Assange (@JulianAssange) April 21, 2017
