VIRGINIA — A Kosovar citizen accused of hacking the personal data of more than a thousand U.S. officials and sending it to Islamic State militants in Syria appeared in federal court in Virginia on Wednesday.

It was the first time Ardit Ferizi, 20, had publicly appeared in the United States since being extradited from Malaysia, where he was detained in October on a U.S. provisional arrest warrant.

Ferizi, who is believed to be the leader of a Kosovar Internet hacking group, hacked the computer server of a U.S. online retailer and stole the personal identification information of 1,351 U.S. military personnel, according to charging documents.

The criminal complaint says Ferizi provided the list to ISISe members, including the British hacker Junaid Hussain, who linked to the list in an Aug. 11, 2015, tweet titled “NEW: U.S. Military AND Government HACKED by the Islamic State Hacking Division!”

Twitter messages from Ferizi to other ISIS-affiliated Twitter accounts show that he also offered to build the group a computer program enabling them to post propaganda that would “never get deleted”, according to court records.

U.S. officials called Ferizi’s case the “first of its kind” when his arrest was announced last year, but he is one of at least 79 individuals whom U.S. prosecutors have charged with ISIS-related crimes in the past two years.

An Albanian interpreter has been appointed in advance of his next court appearance on Friday.

Ferizi faces a maximum sentence of 35 years in prison if convicted.