President Donald Trump is facing criticism after retweeting a post that included the alleged name of the anonymous whistleblower who sparked his impeachment investigation by the House.
Mr Trump retweeted a message from user @Surfermom77 – an account which claims to be a woman named Sophia living in California – on Friday night.
That account includes an unusually high amount of activity and features stock images from the internet which are typically signs of an automated or bot account.
The retweet disappeared on Saturday morning, which suggested Mr Trump had deleted it although it could still be found.
But it reappeared on Saturday night and Twitter told the Associated Press news agency that an outage with one of its systems caused tweets on some account, including Mr Trump's, to only be visible to some users.
The US president has repeatedly supported efforts to unmask the whistleblower, but this is the first time he has directly posted the alleged name on his Twitter feed.
Identifying the whistleblower, who works in the intelligence field, could violate federal protection laws.
In August, the whistleblower filed a complaint about a telephone conversation between Mr Trump and Ukraine President Volodymyr Zelenskiy.
That complaints sparked House Democrats to launch an investigation which ended in Mr Trump's impeachment earlier this month.
It will now head to the Senate, where the Republican majority is expected to acquit the president.
Claims made in the whistleblower's complaint were confirmed during the impeachment hearings by a string of diplomats and other career officials, many of whom testified in public.
The White House also released a transcript of the 25 July phone call, in which Mr Trump asked for help investigating former vice president Joe Biden and the Democratic National Committee.
Whistleblower laws protect the identity and careers of people who bring forward accusations of wrongdoing by government officials.
Mr Trump has insisted he did nothing wrong during his dealing with Ukraine and has claimed the whistleblower made up the complaint. He has also called for the whistleblower to come forward.