"I do not understand why Emmanuel Macron is not integrally focused on organizing a conference for peace to put an end to this [conflict]," Le Pen was quoted as saying by French media.
The leader of the National Rally group in the lower house of parliament spoke to the press on Wednesday during a trip to the riot-hit city of Beauvais, north of Paris.
She warned that a strike "on a third country can trigger a third world war … We do not know how a third country would react if it were hit by a weapon supplied by France."
Macron's decision to supply Ukraine with SCALP missiles, the French equivalent of the United Kingdom's Storm Shadows, prompted a strong reaction from both sides of the political aisle in France. The right-wing Republicans slammed it as escalatory while the leftist France Unbowed warned of a possible direct conflict with Russia.