The Entourage star posted a photograph of New York's World Trade Center on on Friday (11Sep15) to mark the 2001 atrocity, in which the Twin Towers were destroyed and almost 3,000 victims perished.

However, he attracted complaints from some followers by including the caption, "R.I.P. the 2,996 Americans who died in 9/11. R.I.P. the 1,455,590 innocent Iraqis who died during the U.S. invasion for something they didn't do."

Grenier later deleted the post and replaced it with photos of a destroyed Ground Zero, an illustration of New York firemen, and an image of the Twin Towers before the attacks, according to Britain's Daily Mirror newspaper.

Some fans have since vowed to boycott the actor's social media accounts, branding him "disrespectful".

One follower wrote, "Wow, I can only imagine how the 9/11 victims families feel. Today was not the day. Today is their day. Have some class."

A representative for Grenier has yet to respond to the controversy.