US President George W Bush's chief spokesman, White House press secretary Ari Fleischer, has resigned from his post and will leave the administration in the summer.
Fleischer said it was "time to go"
Mr Fleischer, who became one of the most well-known faces of the Bush administration during the 11 September attacks and the wars in Afghanistan and Iraq, is said to be entering the private sector.
"I informed President Bush last week that after 21 years of doing nothing but government and politics... that I have decided that my time has come to leave the White House," he told Reuters news agency.
He also told the Associated Press news agency that he wanted to leave his job before President Bush's re-election campaign got into full swing.
"I believe deeply in this president, his policies and the man," he said.
"But there comes a time in public service when you have to decide when it's time to go."
BBC correspondent Michael Buchanan in Washington says that Mr Fleischer had clashed several times with reporters, and had an uneasy relationship with some members of the Bush administration, although Mr Fleischer says his decision to leave is entirely his own.
President Bush has not yet named a replacement for Mr Fleischer.
However his temporary replacement, deputy press secretary Scott McClellan, is thought to be a possible candidate, as are Republican strategist Ed Gillespie and current Pentagon spokesman Victoria Clarke.
Mr Fleischer, who got married six months ago, joined Mr Bush's camp in 1999 prior to his election in 2000.
He has also previously served as communications director in the presidential campaign of Republican senator Elizabeth Dole, wife of former presidential candidate Bob Dole.