(CNN) An alleged Russian hacker suspected of stealing 117 million LinkedIn passwords in 2012 appeared in federal court in San Francisco Friday morning after being extradited to the United States following a protracted diplomatic struggle between the US and Russia.

Yevgeniy Nikulin, who arrived in the US overnight, faces cyber criminal charges including cyber intrusion and identity theft. Nikulin entered a not guilty plea to all charges. He declined to provide his name and age when asked by the judge, who then advised him of his right to remain silent, noting that he might already be aware of these rights.

The government told the judge that Nikulin poses a serious flight risk and said he is a Russian citizen who was extradited from the Czech Republic. Prosecutors said they have notified the Russian consulate in Houston of Nikulin's extradition and detention.

Nikulin was arrested by Czech police in Prague in 2016 after US authorities issued an international arrest warrant for him. A grand jury indictment filed in 2016 in California charged him with computer intrusion and aggravated identity theft, among other offenses.

According to the indictment, Nikulin managed to break into LinkedIn's computers in March 2012 because he stole the username and password of an employee who worked at the company's Mountain View, California, headquarters.

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