"He had been combative with our staff in jail. Nothing in particular, but he was trying to destroy some jail things," Palmer said on Wednesday. He added that "there was no escape in the court today."
US media reported that Nikulin was kept in shackles during the court session because he had tried to escape.
Palmer confirmed that Nikulin was kept in shackles during his appearance, and court documents said the defendant was kept in "restraints" throughout the session.
The US District Court for Northern California could not provide additional information. “We have no details,” the court spokesperson Lynn Fuller told Sputnik.
Nikulin’s defense attorney did not immediately respond to a request for comment.
"A status hearing regarding the financial affidavit is set for April 30," the document said, adding that the hearing would be presided over by Judge Elizabeth Laporte.
Nikulin was arrested in the Czech Republic on a US arrest warrant in October 2016 for allegedly hacking into computers belonging to LinkedIn, Dropbox and Formspring online services. He was extradited to the United States on March 29.
The Russian Embassy in the United States said it was officially notified by the US State Department about his extradition. On Monday, Russia's Foreign Ministry said Moscow outraged by the decision of the Czech Republic to extradite Nikulin.
Nikulin has also been charged with internet fraud in Russia in 2009. Moscow and Washington both requested Nikulin’s extradition on the same day. The Czech court ruled both requests legal, leaving the decision to the country's Justice Minister Robert Pelikan, who satisfied the US request.
Nikulin has pleaded not guilty to the US charges against him, which include conspiracy, cyber intrusion and aggravated identify theft.