In a letter to its personnel and subdivisions, the Collegium of the State Security Committee of the USSR (KGB) urges operatives to become more vigilant in their work and personal conduct as the 27th Congress of the CPSU approaches and in light of raised international tensions.

This document describes the deficiencies which were made in activities aimed at overlapping of Chernobyl disaster’s consequences. These deficiencies could lead to new victims because the security rules of handling with dangerous radioactive materials were broken.

Radiation levels in Pripyat and the surrounding area following the Chernobyl nuclear disaster.

Physicists at the Academy of Sciences give advice for containing the Chernobyl nuclear disaster.

This KGB report provides a chronology of the Chernobyl nuclear disaster, and gives information on the disaster's first victims.