Rupert Murdoch has defended the decision to cast white actors in the lead roles in Ridley Scott’s new Egypt-based film Exodus: Gods and Kings by claiming that all of the Egyptians he knows are white.

In a tweet, the Australian media mogul, whose 20th Century Fox firm is the film’s distributor, wrote: “Moses film attacked on Twitter for all white cast. Since when are Egyptians not white? All I know are.”

After he was heavily criticised by other users of the site, he added: “Everybody-attacks last tweet. Of course Egyptians are Middle Eastern, but far from black. They treated blacks as slaves.”

And that was followed by a third tweet on the subject, which read: “Okay, there are many shades of color. Nothing racist about that, so calm down!”

After he was the subject of yet more criticism, Murdoch changed his tack, tweeting that he wanted to “change the subject”.

His comments come after director Ridley Scott attributed the casting decisions to a need to attract financial backing.

“I can’t mount a film of this budget, where I have to rely on tax rebates in Spain, and say that my lead actor is Mohammad so-and-so from such-and-such. I’m just not going to get it financed. So the question doesn’t even come up,” he told Variety.

In a curt response to Murdoch’s tweets, the respected media diversity organisation Writers of Colour wrote simply: “Sigh.”