President Emmanuel Macron stated on Thursday that France would respond to Russia’s act of war against Ukraine without hesitation, and that Russia should anticipate strong penalties that will hurt its military, economy, and energy sector.

“Last night’s actions were a watershed moment in European history,” Macron said in a televised speech to the French people, standing in front of the French, European Union, and Ukrainian flags.

“We will reply to this act of war with cold blood, resolve, and solidarity,” he said.

French Foreign Minister Jean-Yves Le Drian had previously stated that France will strengthen its assistance for Ukraine “in all forms,” without clarifying whether or not this included military measures.

On Thursday, Russian soldiers invaded Ukraine, launching a land, sea, and air assault in Europe’s worst strike by one state against another since World War II.

British Prime Minister Boris Johnson, speaking shortly before Macron in a televised address from Downing Street, had also said that Britain and its allies would unleash a massive package of economic sanctions to hobble the Russian economy.

“I don’t believe that the Russian dictator will ever subdue the national feeling of the Ukrainians and their passionate belief that their country should be free,” he said.

Western leaders are due to discuss further steps during several high-level formats on Thursday, including an emergency NATO meeting.