Saudi state security on Sunday said two men who had planned an "imminent terrorist operation" were killed by security forces in the eastern city of Dammam, Saudi state agency SPA said.

During the operation 5 kilogrammes of explosive materials were seized, SPA said.

It was not immediately clear whether this was the same incident as reported by Saudi state media on Wednesday, in which two "terrorists" were killed by security forces after a shooting in a residential neighbourhood of Dammam.