China and Russia have modified an important layer of the atmosphere above Europe to test a controversial technology for possible military application, according to Chinese scientists involved in the project.

A total of five experiments were carried out in June. One, on June 7, caused physical disturbance over an area as large as 126,000 sq km (49,000 square miles), or about half the size of Britain.

The modified zone, looming more than 500km (310 miles) high over Vasilsursk, a small Russian town in eastern Europe, experienced an electric spike with 10 times more negatively charged subatomic particles than surrounding regions.

In another experiment on June 12, the temperature of thin, ionised gas in high altitude increased more than 100 degrees Celsius (212 degrees Fahrenheit) because of the particle flux.