A UKRAINIAN man has shot dead three security guards and seriously injured another after being detained for stealing a computer memory stick, police said.

The man pocketed the USB flash drive in a store inside a mall on the outskirts of the capital Kiev before being spotted by guards and taken into a separate room for questioning.

The man opened fire shortly after he entered the room then made his escape.

Police said they had launched a city-wide search for the man, whose identity was not immediately released.