Former US national security adviser John Bolton has reappeared on Twitter, claiming he was barred from accessing his account after he was fired in September or, as he tweeted, "since he resigned."
"We have now freed the Twitter account, which was previously unfairly banned following my resignation as a national security adviser," he said in a tweet, accusing the White House of closing his account.
“Out of fear for what I might say? To those who speculated that I disappeared. "I'm sorry I disappointed you."
Bolton's name has been echoed over and over again during the ongoing default against US President Donald Trump. Witnesses said he was familiar with, and opposed, the back channel of pressure on Ukraine, at the heart of the investigation.
His lawyers have indicated that he may have additional information for members of Congress.
In an interview on Fox News, Trump denied the White House had closed the account.
Bolton's account was opened in 2010, long before he joined the Trump administration. It was not clear exactly why the account was closed.
Bolton has spoken publicly since he left the White House and used to appear regularly on news programs, sparking controversy as to whether he needed calculation to speak.
Bolton served in the Bush administration and was fiercely opposed to the war in Iraq. He was one of the Trump administration's hawks over Iran and Venezuela.