March 9 (Reuters) - A Ukrainian man charged last year with conducting one of the most severe ransomware attacks against U.S. targets has been extradited to the United States and made a court appearance on Wednesday, the U.S. Justice Department said.

According to an August 2021 indictment, Yaroslav Vasinskyi, 22, accessed the internal computer networks of several victim companies and deployed Sodinokibi/REvil ransomware to encrypt the data on their computers, the Justice Department said in a statement.

Vasinskyi was allegedly responsible for the July 2021 ransomware attack against Florida software provider Kaseya, the department said.

Reuters could not reach a representative of Vasinskyi. Kaseya did not immediately return a message seeking comment.

The Ukrainian national was accused in the indictment of breaking into Kaseya over the July 4 weekend last year, and simultaneously distributing with accomplices REvil ransomware to as many as 1,500 Kaseya customers, encrypting their data and forcing some to shut down for days, the Justice Department said.

While most of the 1,500 businesses paralyzed as a result across the globe faced limited concerns, the disruption was felt keenly in places like Sweden, where hundreds of supermarkets had to close because their cash registers were inoperative, or New Zealand, where schools and kindergartens were knocked offline.

Vasinskyi was charged in the indictment with breaking into the victim companies and installing encryption software, developed by the core REvil ransomware hacking group. REvil directly handled the ransom negotiations and split the profits with affiliates like Vasinskyi. This model allowed the notorious ransomware gang to extort numerous companies for cryptocurrency.

Vasinskyi was arrested in Poland in October, and charged late last year along with a Russian by the Justice Department.

Vasinskyi was transported to Dallas by U.S. law enforcement authorities where he arrived on March 3, the Justice Department said on Wednesday.

REvil was involved in an attack last year against top global meatpacker JBS SA.

(Reporting by Kanishka Singh in Bengaluru and Raphael Satter in Washington; Editing by Leslie Adler and Karishma Singh)