A Romanian hacker known as 'Guccifer' who posted unofficial emails sent to then-Secretary of State Hillary Clinton on the Internet was extradited from Romania and made his first court appearance in the United States on Friday.

Marcel Lehel, 44, is charged in a nine-count indictment that includes three counts of gaining unauthorized access to protected computers, the U.S. Justice Department said in a statement.

According to the indictment, Lehel 'hacked into the email and social media accounts of high-profile victims, including a family member of two former U.S. presidents, a former U.S. Cabinet member, a former member of the U.S. Joint Chiefs of Staff and a former presidential advisor,' the statement said.

Marcel Lehel, 44, a Romanian hacker known as 'Guccifer' who posted unofficial emails sent to then-Secretary of State Hillary Clinton on the Internet was extradited from Romania and made his first court appearance in the United States on Friday (file photo from 2014)

He shot to fame in 2013 after he claimed responsibility for hacking into George W. Bush family emails and posted artwork by the former president (right)

It did not name the victims, but in 2013 news websites published hacked emails sent to Clinton by her former adviser Sidney Blumenthal, offering the first public clues about Clinton's unconventional email arrangements and attributing the hack to Guccifer.

Clinton, the front-runner in the race for the Democratic 2016 presidential nomination, has apologized for using a private email server for official business while secretary of state from 2009 to 2013.

The FBI is conducting an inquiry into the arrangement.

Guccifer shot to fame in 2013 after he claimed responsibility for hacking into George W. Bush's family emails and posted artwork by the former U.S. president, including self-portraits in the bathtub.

He also distributed emails exchanged by former U.S. Secretary of State Colin Powell and Corina Cretu, a Romanian member of the European Parliament, prompting Powell to deny the two had had an affair.

A Romanian hacker known as 'Guccifer' who posted unofficial emails sent to then-Secretary of State Hillary Clinton on the Internet was extradited from Romania and made his first court appearance in the United States on Friday.

Lehel, a cab driver by trade, was arrested in Bucharest in January 2014.

He was serving a combined seven-year sentence in Romania, including a four-year term handed down in 2014 for illegally accessing email accounts of public figures.

Last month, a source with Romania's DIICOT anti-organized crime and terrorism unit told Reuters that the country's top court had 'approved an 18-month temporary extradition to America for the hacker.'

According to the U.S. indictment, Lehel 'publicly released his victims' private email correspondence, medical and financial information and personal photographs,' the Justice Department statement said.

Lehel appeared in federal court in Alexandria, Virginia.

The other charges in the indictment are three counts of wire fraud, and one count each of aggravated identity theft, cyberstalking and obstruction of justice, it said.

The statement did not say what punishment the charges carried.