Ursula Von der Leyen was told Brussels has "become a swamp" in last night's debate between the eight candidates standing to be the next EU Commission President.
Anders Vistisen, the candidate for the right-wing Identity and Democracy group, warned Von der Leyen that, if he were elected, he would "fire 10,000 bureaucrats in Brussels", including the EU Commission President herself.
In a fiery intervention, he said: "Brussels has become a swamp … we will begin by firing 10,000 bureaucrats in Brussels, and I would like to start with you, Ursula von der Leyen."
But Von der Leyen hit back: "We will not allow that you destroy the European Union."
Ursula Von der Leyen was told Brussels has "become a swamp" in last night's debate between the eight candidates standing to be the next EU Commission President
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She added: "We are stronger than you, and we will fight your interference with all means."
Last night's debate also saw Von der Leyen signal a new willingness to cooperate with the European Conservatives and Reformists group - whose MEPs belong to groups including Giorgia Meloni’s Brothers of Italy and Poland’s Law and Justice party.
She said: "It depends very much on how the composition of the Parliament is, and who is in what group."
In February, Von der Leyen announced her plan to run for a second term as European Commission President following months of speculation.
The European Commission President made the announcement at an event held by her Christian Democratic Union (CDU) Party in Berlin.
She is expected to run her campaign on a platform of increased defence spending for the EU, unveiling plans to "install a commissioner for defence" if she wins a second term.
In February, Von der Leyen announced her plan to run for a second term as European Commission President following months of speculation
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While Von der Leyen is the frontrunner to win the EU elections this summer, some officials have argued that her political errors are catching up with her.
Speaking to Politico earlier this month, one official said: "A big part of it is the arrogance of power.
"She mistakenly thought she could get away with everything.
"So some smaller mistakes are now being used against her."