The U.K. Defense Ministry is investigating reports that a Russian warship fired warning shots at a British yacht in the English Channel.

A British official familiar with the incident said reports had been received from a U.K.-registered yacht alleging that a Russian navy vessel fired warning shots nearby, around 500 yards away.

They added that the incident was understood to have taken place outside U.K. territorial waters around 20 nautical miles south of the Isle of Wight, a small island off England’s south coast.