BRUSSELS - European Parliament President Martin Schulz on Wednesday called for closer cooperation among European Union (EU) institutions at a time of multiple crises.

"The situation in many member states is that Xenophobia is growing, the euro is being called into question and Europe's open internal borders within the Schengen area are threatened," the president said in a speech to members of European Commission, the EU's executive body.

"In the past few months we have witnessed a disturbing trend towards 're-nationalization' and 'summitization': the heads of state and government are arrogating more and more decisions to themselves, debating and taking decisions behind closed doors," he added, complaining about growing power shift from EU institutions back to national governments.

Schulz's pessimistic comments came as the 27-member bloc has been trapped in a sovereign debt crisis in the eurozone, the Schengen agreement and border control disputes, and widespread social crises across Europe.

Also on Wednesday, European Council President Herman Van Rompuy warned in Romania that the "winds of populism" were affecting the free movement of persons within the Schengen area, one of the EU's key achievements.

Worries about "populism" at the EU level has been largely fueled by a surprise support record claimed by French far-right National Front leader Marine Le Pen in the first round of French presidential election on Sunday. Nearly one in five French voters supported the far-right party in the voting.