Leaked Russian military files reveal that Putin's forces have been practising the use of tactical nuclear weapons in the early stages of a conflict with a major global power, including potential invasion scenarios by China.

The classified documents, which were reviewed by the Financial Times, suggest a lower threshold for deploying such weapons than Russia has previously admitted to publicly, according to experts who verified the papers.

Leaked Russian military files reveal that Putin's forces have been practising the use of tactical nuclear weapons in the early stages of a conflict with a major global power, including potential invasion scenarios by China.

The classified documents, which were reviewed by the Financial Times, suggest a lower threshold for deploying such weapons than Russia has previously admitted to publicly, according to experts who verified the papers.