Key European Union nations France and Germany are opposed to new EU proposals to help Italy and Greece cope with a massive influx of migrants crossing the Mediterranean.

The EU's executive Commission has a plan for sharing Syrian and Eritrean refugees over the next two years, as thousands of migrants attempt the perilous sea crossing. The system would see France and Germany host many of them.

The French and German interior ministers said in a statement Monday that the formula "should take more properly into account the efforts already made by member states regarding international protection, and other forms of assistance."

The Commission will propose a permanent system late this year for use during high migration flows but the ministers insist that it should "remain temporary and exceptional."