MELBOURNE (Reuters) - Australian federal police were on Monday investigating a social media post by a government lawmaker that showed him aiming a gun and taunting left-wing green supporters.

The rural-based Nationals Party lawmaker George Christensen posted the picture of himself on Facebook aiming a gun and asking: “You gotta ask yourself, do you feel lucky, greenie punks?” echoing a line from Clint Eastwood’s “Dirty Harry” movie.

Greens Party leader Richard Di Natale reported the post to Australian police on Sunday and asked Prime Minister Malcolm Turnbull to force Christensen to take it down, noting the timing of the post just days after 17 people were killed in the deadliest high school shooting in U.S. history.

“17 kids gunned down in cold blood and he thinks this is ok? He’s not fit to be an mp (member of parliament),” Di Natale said on social media.

Turnbull said on Monday the post was “very inappropriate” and it had been removed, declining to comment further during a radio interview because the matter had been referred to police.

The Australian Federal Police told Reuters the matter is “being assessed” and declined to comment further.

Christensen has refused to apologize for the post, saying in another post that it was a “tongue-in-cheek Dirty Harry photo” and that green activists who protested at mine sites and along coal rail lines were a bigger danger than guns.

“They are the ones actually putting real lives at risk -- not only of their own protesters who go about things illegally, but also for the workers who are up there,” he told reporters on Monday.

After Greens supporters complained, Christensen initially changed his comment on the picture to: “You gotta ask yourself, do you have a sense of humor, greenie punks? Obviously not,” then later removed the post.