Federal prosecutors in the U.S. have warned that data belonging to users of Megaupload could start getting deleted by Thursday.

Prosecutors have blocked any access to Megaupload and have charged seven men, including founder Kim Dotcom, based in New Zealand. It has been alleged the site has assisted millions of illegal downloads of movies, music and other downloadable content.

A letter filed in the case on Friday by the U.S. attorney's office, said that storage companies Carpathia Hosting and Cogent Communications Group could begin deleting data as soon as Thursday. The letter also said the government has copied some data from the servers but did not take them physically, and now that it had executed its search warrants.

Prosecutors also said that the servers were controlled by Carpathia and Cogent and issues about the future of the data must be resolved with them.

Hong Kong-based Megaupload is known to hire outside companies to store the data for a fee. However, after the government froze its money, those companies are not getting paid, according to Megaupload attorney Ira Rothken. The company also said that its millions of users stored their own data, including family photos and personal documents.

Rothken also said the company was working with prosecutors to try and prevent the data from being deleted. He added that at least 50 million Megaupload users had data which are in danger of being permanently erased.

However, spokespersons from both Carpathia and Cogent haven’t responded about the ongoing issue, according to a Guardian report.