BERLIN (AP) - The European Union is urging its 27 member states to test wheat shipments from the United States after unauthorised genetically modified (GM) grains were found in Japan.

Tokyo on Thursday halted imports of certain types of wheat from the US following the discovery of an experimental strain that was tested by Monsanto but never approved.

The EU's consumer protection office said on Friday that shipments which test positive should not be sold in line with the bloc's "zero tolerance" for GM crops.

It also said it was seeking "further information and reassurance" from US authorities and had asked Monsanto for help in developing a reliable test for the GM grains.

The European Union imports more than 1.1 million tonnes of US wheat each year, mostly to Spain.