Manfred Weber said in Sofia that "the state must win over the human traffickers in the fight against illegal migration."
The center-right European People's Party candidate, who is also running to replace Jean-Claude Juncker as European Commission president, visited Bulgaria on Sunday as part of his campaign and to back the country's ruling center-right GERB party in next weekend's elections.
The German's words about illegal migration, which is of significant concern for voters in Bulgaria, received frenetic applause by the 14,000 GERB supporters.
The Balkan country has taken a tough stance against mass migration to Europe by sealing off its border to Turkey with a barbed-wire fence to prevent migrants from entering.
Weber praised the diversity of the European continent but added that there is one thing in common - "it is based on Christianity and we are proud of this."
Bulgaria, which joined the European Union in 2007, will elect 17 members of the European Parliament's 751 seats on May 26.
According to the latest polls, only three parties will pass the 5.8 percent threshold in the elections - the GERB party, the Socialist party, and the liberal Movement for Rights and Freedoms.
The ruling GERB party of Prime Minister Boyko Borissov, which has won almost every national and European election in the last decade, has suffered a setback because of recent scandals over murky real estate deals and the misuse of EU funds by senior officials and is facing now a serious challenge from the opposition Socialists.
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