French President Emmanuel Macron called Russia an adversary that would not stop if it defeated Ukraine, urging Europeans to not be "weak" and to get ready to respond.

Macron caused controversy last month after he said he could not rule out the deployment of ground troops in Ukraine, with many leaders distancing themselves from that while others, especially in eastern Europe, expressed support.

"If Russia wins this war, Europe's credibility will be reduced to zero," Macron said in a TV interview mostly directed at a domestic audience, after French opposition leaders criticized his comments as bellicose.

Macron said he "deeply" disagrees with the opposition leaders.

"Today, deciding to abstain or vote against support to Ukraine, it's not choosing peace, it's choosing defeat. It's different," he said.

Macron's main opposition party of conservative Marine Le Pen abstained in parliament on a vote earlier this week about a security pact France signed with Ukraine, while the hard-left France Unbowed party voted against it.

"If war spread in Europe, Russia would be to blame," Macron said. "But if we decided to be weak, if we decided today that we would not respond, it would be choosing defeat already. And I don't want that."

He said it was important for Europe not to draw red lines, which would signal weakness to the Kremlin and encourage it to push on with its invasion of Ukraine. He refused to give details on what a deployment to Ukraine might look like.

"I don't want to do so. I want Russia to stop this war and retreat from its positions and allow peace," he said. "I'm not going to give visibility to someone who is not giving me any. This is a question for President [Vladimir] Putin. I have reasons not to be precise."

Macron said France would never initiate an offensive against Russia, and that Paris was not at war with Moscow, even though Russia launched aggressive attacks against French interests in and outside France.

"The Kremlin regime is an adversary," he said, declining to call Russia an enemy. He also said Putin's threats about nuclear strikes were "not appropriate."

Macron said Ukraine was in a "difficult" situation on the ground and that stronger support from allies was necessary.

"Peace does not mean the capitulation of Ukraine," he said. "Wanting peace does not mean defeat. Wanting peace does not mean dropping Ukraine."

He also said he hoped the time would come one day to negotiate peace with a Russian president "whoever it might be," for the first time envisaging the possibility of Putin no longer being in charge in Russia.