European leaders fear a knock-down-drag-out trade war with the United States far more than their counterpart in the White House.

Without a preliminary agreement, broad U.S. tariffs on most imports would rise from their current 10% to the rate set out by President Donald Trump on April 2. In the EU's case that would be 20%. The Commission said that at one point the United States had mooted a 17% tariff on EU agri-food imports, the sources said.

The European Union expects to find out on Monday whether President Trump will impose more tariffs, in a move economists have warned would have repercussions on both sides of the Atlantic.