The British government says it is investigating how secret defence documents were recovered from a bus stop in England.

The secret documents outlined the movement of the warship, prompting Russia to fire warning shots off the coast of Crimea.

According to the foreign news agency ‘AFP’, the British Ministry of Defense said that an employee told him last week that these documents had gone missing for which an investigation has been started.

“It shouldn’t have happened,” Northern Ireland Minister Brandon Lewis told Sky News.

“It was reported at a time when the situation is being investigated internally,” he said.

An anonymous source told the BBC that he had found 50 pages of classified documents behind a bus stop in southern England.

According to the BBC, the documents spoke of a possible Russian reaction to the British HMS defender, a warship that was travelling in Ukrainian waters off the coast of Crimea.

Russia said on Wednesday it has fired warning shots at a Navy ship in the Black Sea for violating its territorial waters.