Strange Circles on Sky

Date: 28th July, Place: Murmansk City, Russia. Suddenly some strange circles appeared on the sky. Look at the pictures! According to the photographer, these smoky circles appeared suddenly, without any sound of flying jet and there are even no air bases in that area. So it was a matter of curiosity for all.

But we think that it was nothing but just smokes left by a jet. What you think?