Belgian Prime Minister Charles Michel, French President Emmanuel Macron, Luxembourg's Prime Minister Xavier Bettel and Dutch Prime Minister Mark Rutte (from L to R) attend a meeting in Bourglinster, Luxembourg, on Sept. 6, 2018. Luxembourg's Prime Minister Xavier Bettel hosted the Belgian, Dutch and French leaders for a working lunch on Thursday, during which they discussed, among other things, the future of Europe. (Xinhua/SIP/Jean-Christophe Verhaegen)

BRUSSELS, Sept. 6 (Xinhua) -- Luxembourg Prime Minister Xavier Bettel hosted the Belgian, Dutch and French leaders for a working lunch on Thursday, during which they discussed, among other things, the future of Europe.

French President Emmanuel Macron, Belgian and Dutch prime ministers Charles Michel and Mark Rutte have joined Bettel to discuss the fundamental values of the European Union, Brexit and the intensifying migrant crisis.

At a press conference held in the grand Bourglinster Castle, Bettel stressed the need to protect the fundamental values of the European Union at all costs.

On the subject of the migration crisis, he said that there is "no miracle solution, (and) we must find peace in the affected countries", adding that he "regrets the lack of solidarity in Europe".

Macron, in his own statement, said it is the duty of every European country to take responsibility for managing the migratory problem and spoke of "a more united, more sovereign Europe on defense and the economy".

"The nationalists propose to host no one, not to respect the right of asylum. This is contrary to the history and values of Europe. Their solutions are neither humane nor effective," Macron told reporters.

Macron, who has been pushing for the constitution of a "progressive" platform in anticipation for the European elections next May, invited on Thursday the European People's Party (EPP) to clarify its position, saying it could not be alongside both German Chancellor Angela Merkel and Hungarian Prime Minister Viktor Orban simultaneously.

Belgian Prime Minister Charles Michel spoke about Europe's values and migration, saying that "the migratory question will mobilize us for years".

The leaders of France, Belgium, Netherlands and Luxembourg have also warned the British government that they will neither allow cherry-picking of European Union rules, nor risk the bloc's unity for a Brexit accord, according to media reports.