SAN FRANCISCO — A Russian national accused of hacking into computers belonging to LinkedIn, Dropbox and Formspring has pleaded not guilty to all charges in a nine-count federal criminal indictment handed down in 2016.

Yevgeniy Aleksandrovich Nikulin, 30, of Moscow, made his first appearance in an American courtroom Friday after being extradited from the Czech Republic. Nikulin was arrested there Oct. 5, 2016, under an Interpol Red Notice, and he's remained in Czech custody since.

The allegations against Nikulin date back to 2012. Among other things, Nikulin is accused of stealing usernames and passwords of Formspring users. The social question-and-answer platform rebranded to Spring.me after it was forced to reset all 28 million users' passwords after 420,000 passwords were posted to an internet forum. The company has since rebranded again as  Twoo.

Justice Department offices on Friday attempted to tie Nikulin's arraignment to broader efforts at addressing Russian hacking.

“Computer hacking is not just a crime, it is a direct threat to the security and privacy of Americans,” U.S. Attorney General Jeff Sessions said in a press release issued shortly after Friday's hearing. “In this case, the defendant, a Russian national, is accused of breaking into the computer system of several important American companies using stolen identities, and potentially gaining access to the personal information of millions of Americans.

“This is deeply troubling behavior once again emanating from Russia. We will not tolerate criminal cyberattacks and will make it a priority to investigate and prosecute these crimes, regardless of the country where they originate,” Sessions said.

Nikulin, who was represented by Assistant Federal Public Defender Gabriela Bischof at Friday's hearing before U.S. Magistrate Judge Jacqueline Scott Corley of the Northern District of California, wore a gray hooded sweatshirt with black elbow patches and gray sweatpants, and listened to the proceedings through an interpreter. Nikulin spent most of the hearing looking around the courtroom, and refused to answer when Corley asked him for his name and age. Corley advised him of his right to remain silent, which she noted he “seem[ed] to be aware of.”

Assistant U.S. Attorney Michelle Kane asked that Nikulin be detained saying he is a “serious risk of flight.”

The U.S. Marshals Service, however, declined to take Nikulin into custody because he was medically cleared by a paramedic rather than a doctor. The FBI agents who traveled with Nikulin from the Czech Republic were set to get Nikulin evaluated after Friday morning's hearing and return him to the Marshals. A detention hearing in Nikulin's case is set for Wednesday, April 4.