“We have undoubtedly been too hesitant by defining the limits of our action to someone who no longer has any and who is the aggressor,” he continued.

He said he’d consider sending French troops to Ukraine “if the Russians were to break through the front lines, if there were a Ukrainian request, which is not the case today.”

He added that if Russia defeated Ukraine, it would then probably seek to attack another European country.

In recent months, political and military leaders have been issuing increasingly stark warnings about the possible consequences of a Russian victory in Ukraine.

Macron’s remarks about sending French troops to defend Ukraine are among the most hawkish by a Western leader.

Ukraine has struggled to prevent Russia from breaking through its defensive lines amid a US aid block. And though the $61 billion aid bill was recently passed, Ukraine is still fighting to hold back intensifying Russian attacks.

While NATO countries have sent money and weapons to help Ukraine, they’ve avoided a direct confrontation amid fears it could escalate the conflict with a nuclear-armed Russia.

Under Article 5 of NATO’s founding treaty, members are pledged to defend each other if attacked.

In response to Macron’s earlier remarks, the Kremlin’s spokesperson, Dmitry Peskov, said deploying NATO troops to Ukraine would lead to war between Russia and the alliance.

“We would need to talk not about the probability, but about the inevitability,” Peskov said, according to Radio Free Europe/Radio Liberty.

Analysts recently discussed with Business Insider the likelihood of Russia attacking NATO, with the Russian-military expert Ruth Deyermond saying Putin’s regime was too weak militarily to risk a direct confrontation with NATO.

In the interview with The Economist, Macron said he was determined to prevent a Russian victory.

“We mustn’t rule anything out,” he said, “because our objective is that Russia must never be able to win in Ukraine.”