"That is probably the biggest frustration I had when today you see that the European borders have been closing. And that has been a very negative signal to the rest of the world," Guterres said.
"When I look to this policy, in which several countries in Europe are closing their borders namely invoking security reasons, they are to a certain extent paying the price of the fact that integration policies in the recent past were not sufficiently effective, that there was not enough investment in creating the conditions for societies that are all becoming multiethnic, multireligious, multicultural to be able to understand that, to live together," Guterres said.
The UN chief nominee added that when he was the Portuguese prime minister he tried to explain people how important migration for the country was.
"I remember that we decided to tell the truth to the people and to say, look, we, Portuguese, have the fertility index of 1.3 at time, which means that we cannot survive as a nation without migration," he said.
The politician added that Russia was a good example of building a multicultural society with many nations living together in peace.
The European Union is currently struggling with a massive influx of migrants as hundreds of thousands of people are fleeing conflict-torn countries in the Middle East and North Africa and heading for Europe in hopes of a better life there.
Guterres is one of nine candidates to succeed UN Secretary-General Ban Ki-moon on January 1, 2017. He served as Portuguese Prime Minister in 1995-2002 and as UN Refugee Agency High Commissioner in 2005-2015.