U.S. President Barack H. Obama is cutting short a trip to Ireland, and is returning to the U.S. Monday, after arriving Sunday night. Obama is leaving because of the expected arrival of a large plume of smoke from the eruption Sunday of Iceland's Grimsvotn volcano.

EU officials said Monday that they feared that, contrary to what had previously been thought, there was a good chance that smoke from the volcano would affect other European countries – especially Britain and Ireland. The large smoke cloud is on its way south, and will reach either or both countries either late Monday or on Tuesday.