A sonic boom-type noise has been heard across the south west of England which made homes and windows shake.
People took to social media at about 15:00 GMT to report the "huge bang" that lasted several seconds.
It was heard in the Dorchester and Weymouth areas in Dorset and also Taunton, Bridgwater and Wellington in Somerset and parts of Devon.
A Ministry of Defence spokeswoman said the noise was not believed to be linked to any RAF aircraft.
Ollie Peart, of Dorchester, managed to capture the noise on his security camera and described it as a "massive bang".
Others posted on Twitter that their homes and windows shook.
BBC reporter Linzi Kinghorn, who was on the Isle of Portland at the time, said: "It was a very loud, sounded like thunder and lasted about 10 seconds."
Police forces including Dorset, Devon and Cornwall and Avon and Somerset Police said they had no incidents reported which related to the noise.