In March 1992, Yeltsin would hand over KAL 007's black box without its tapes to South Korean President Roh Tae-woo at the end of the plenary session of the South Korean National Assembly with this statement, "We apologize for the tragedy and are trying to settle some unsolved issues." Yeltsin released the tapes of the KAL 007's "Black Box" (its Digital Flight Data Recorder and Cockpit Voice Recorder) to the International Civil Aviation Organization (ICAO) on 8 January 1993. For years the Soviet authorities had denied possessing these tapes. The openness of Yeltsin about POW/MIA and KAL 007 matters may also have signalled his willingness for more openness to the West. In 1992, which he labelled the "window of opportunity", he was willing to discuss biological weapons with the United States and admitted that the Sverdlovsk anthrax leak of 2 April 1979 (which Yeltsin had originally been involved in concealing) had been caused as the result of a mishap at a military facility. The Russian government had maintained that the cause was contaminated meat. The true number of victims in the anthrax outbreak at Sverdlovsk, about east of Moscow, is unknown.