Following a report over the weekend indicating that British and American intelligence services have hacked into video feeds generated by Israeli drone aircraft and fighter jets, Israel's Yedioth Ahronoth is now reporting that the surveillance of Israeli military operations was more extensive than initially reported, compromising information on Israel's Black Sparrow missile project, part of the country's Arrow missile interception program.

The information on the alleged U.K.-U.S. intelligence operation, code-named Anarchist, was said to be based on documents made public by Edward Snowden, the former U.S. National Security Agency contractor, according to simultaneous reports from U.S.-based website The Intercept, Germany's Der Spiegel news weekly and Yedioth.

Yedioth reported that the purported breach of Israeli intelligence information over a period of years was the most serious in the history of the Israeli intelligence community, although, at least with respect to the initial report over the weekend, one Israeli source speaking to Haaretz said the revelations were not "very dramatic" and that Israel's "defense operations were not harmed."

The Black Sparrow missile, which is produced by Israel's Rafael Advanced Defense Systems in cooperation with the U.S. defense firm Raytheon, is reportedly designed to simulate missiles for purposes of testing the Arrow and other missiles.

The surveillance of the Black Sparrow project was a secondary operation of the Anarchist program and was code named Runway, Yedioth reported. The Anarchist program has reportedly been conducted for years from a fortified site in the Troodos mountains in Cyprus by Britain's Government Communications Headquarters in collaboration with the U.S. National Security Agency.