Three sketches possibly drawn by Leonardo da Vinci have been found on the back of one of the master's major works, the Louvre museum said yesterday.

The museum said in a statement that the drawings were found when da Vinci 1500s oil Virgin And Child With St Anne was undergoing routine examination in the Louvre laboratory.

"When taking down the work, a curator noticed two barely visible sketches on the back, representing a horse's head and half a skull," the Louvre said. Further examination revealed a third sketch, a Baby Jesus and Lamb.