(Bloomberg) -- Documents containing classified information from the U.K. Ministry of Defence were found “in a soggy heap” by an anonymous person at a bus stop in Kent, the BBC reported on Sunday.

The “almost 50 pages” describe details of British military operations, including Royal Navy warship HMS Defender’s passage through Ukrainian waters off the Crimea coast last week, and the likely Russian reaction.

They also detail plans for a possible U.K. military presence in Afghanistan after the U.S.-led NATO operation there concludes.

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“There’s an internal investigation into that situation,” Northern Ireland Secretary Brandon Lewis told Sky News on Sunday. “It’s something that none of us want to see.”

Most of the documents were marked “official sensitive,” which is a “relatively low level” of classification, he BBC reported.

An exception was one “Secret U.K. Eyes Only” document addressed to Defense Secretary Ben Wallace that outlines a U.S. request for British assistance in Afghanistan, and asks whether any British special forces will remain in the country once the American withdrawal is complete.

The BBC didn’t report further details of the Afghanistan operation described on the documents due to the sensitivity of the matter. A ministry spokesperson told the BBC that an employee had reported the loss of sensitive papers, adding that “it would be inappropriate to comment further.”

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