PARIS (AFP) - French far-right leader Marine Le Pen faced sharp criticism on Wednesday after tweeting a graphic image of an Islamic State in Iraq and Syria (ISIS) beheading in response to a TV journalist who likened her National Front party to the militant group.

"This is Daesh (an Arabic acronym for the group)," Le Pen fired back in a series of tweets picturing grisly ISIS atrocities.

In one image, a bloodied body lay with his decapitated head on his chest, another depicted a man on fire in a cage, while a third showed a victim being driven over by a tank.

Prime Minister Manuel Valls described the photos as "monstrous".

"Madame Le Pen: inflaming public debate, political and moral failing, non-respect for victims," he wrote on his Twitter account.

Le Pen was reacting to comments by BFM journalist Jean-Jacques Bourdin, who she accused of drawing parallels between her National Front (FN) party and ISIS in an "unacceptable bungle".

Bourdin, during his show known for combative one-on-one interviews, posed a question to Arab world expert Gilles Kepel in which he suggested there were "links" between FN and ISIS as both sought to push the French to cling to their cultural identity.

Le Pen's FN scored a record number of votes in regional elections on Sunday, boosted by concerns over the migrant crisis and terrorism, though they failed to win control of any regions.

The Nov 13 attacks in Paris, which left 130 people dead, led to Le Pen warning that, if ISIS is not conquered, "Islamist totalitarianism will take power in our country".