PARIS—Conservative French presidential candidate François Fillon is campaigning for a tougher, more united Europe that can defend itself against violent extremists and unfair trade — and warns that a “Frexit” would lead to chaos and the death of the EU.

Most of the 11 French presidential candidates are skeptical about the 28-nation European Union, amid growing nationalist sentiment around Europe and Britain’s pending exit from the bloc, called Brexit. Some, like far-right French presidential candidate Marine Le Pen, even support “Frexit” — a French departure from the EU.

But Fillon argued Thursday the EU is “indispensable to ensure the French, and all Europeans, security and economic prosperity.”

Fillon warned that Le Pen’s proposals to leave the EU and the shared euro currency “would be assured chaos, and the implosion of Europe.”

If France were to quit the EU — founded 60 years ago to prevent future world wars — the bloc would likely collapse.

Fillon was once the front-runner in the French presidential race but corruption allegations have hurt his chances in the two-round April 23-May 7 election.

Read more: French presidential candidate Fillon won’t back down amid corruption allegations

In this video from January, French conservative presidential candidate Francois Fillon and his wife were questioned for five hours by police investigators as part of a probe into allegations that Penelope Fillon had been paid for fake jobs.

Fillon acknowledged that the “Brussels machine” has become too powerful and that the bloc has become too heavily regulated and needs to “recreate itself.” So he proposed tougher protection for the EU’s external borders and said EU members should align their asylum and deportation practices.

He also said Europe should defend itself against trade threats, arguing for tougher EU rules against possible trade dumping and tax evasion by U.S. or Asian companies.

“We are in a world of competition where each defends its interests tooth and nail. We should do the same,” he told reporters in Paris.

Pledging to boost French defence spending, he said European countries should stop assuming that NATO or the U.S. will defend Europe.

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Several of the 11 candidates argue either for a “Frexit” — a French departure from the EU — or some other reduced role for the EU.

Rival independent candidate Emmanuel Macron, seen as the front-runner in the presidential race, says the EU needs to defend its common ideals of peace, prosperity and freedom. He wants the EU to stand up to those who “openly want a weakening of Europe: Donald Trump, Vladimir Putin, as well as the main authoritarian leaders of the Middle East.”

The top two vote-getters on the April 23 presidential ballot will go into a presidential runoff on May 7.

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