European stock markets ended lower Monday after comments from euro-zone officials caused investors to reassess the Group of 20 industrial and developing nations' pledge to tackle the euro-zone debt crisis and as data failed to offer any evidence of an upturn in global economic growth.

But early gains were unsustainable and national indexes soon began their southward passage after German Finance Minister Wolfgang Schaeuble said the forthcoming European Union summit isn't a solution to the euro-zone debt crisis in and of itself....