American spy satellites detected increased activity at the Novaya Zemlya test site last week, suggesting that Russia is preparing a nuclear bomb test. "Russia does not perform nuclear testing and does not make preparations to carry them out in the future," said deputy nuclear minister Victor Mikhailov in an interview with ITAR-TASS on Friday, September 25.

"Hydrodynamic experiments are another matter. This is a domestic issue, both Russia and the U.S. perform them," added Mikhailov.

The hydrodynamic experiments (or subcritical experiments) contain the ingredients of a nuclear bomb, but fizzle out without any thermonuclear blast and are not accompanied by radioactive emissions. The tests are used for both improving old warheads and for developing new nuclear devices. Last year, the U.S. conducted three subcritical tests at the Nevada test site, and another last Saturday. These experiments do not violate the Test Ban Treaty, signed both by Russia and the U.S.

According to Minatom’s press service chief, Yuri Bespalko, Russia has conducted subcritical tests at Novaya Zemlya since 1995. This year one such test is scheduled for late autumn. There are plans for the next year as well, say Minatom officials. No dates were provided.