European countries should respond firmly to Donald Trump whenever the U.S. president undermines the integrity of the European Union by advocating other countries follow Britain's decision to leave the EU. 

"Whenever there are statements coming from the president of the United States on Europe and whenever he talks of Brexit as a model for other countries, I believe we should respond," Francois Hollande said on the sidelines of a summit in Portugal, according to French media. 

Southern European leaders were meeting in Lisbon to discuss growing challenges, from the refugee crisis to rising borrowing costs and low economic growth, at a time when rising populism has increased political uncertainty in Europe. 

Hollande is scheduled to have a telephone conversation with Trump later on Saturday. ---Reuters

Source :NNA