KIEL (Reuters) - Germany's veteran Finance Minister Wolfgang Schaeuble made an impassioned plea for a stronger, unified European Union on Sunday (June 19), days before Britain votes on whether to leave the bloc.

Schaeuble did not mention Britain directly but said no country in Europe would be able to cope with the challenges of the 21st century on its own.

"Our European (Union) is not perfect," Schaeuble said in a speech during an award ceremony at the IfW economic institute in Kiel, "but it remained the best way to confront issues including the regulation of financial markets and global warming.

"We should preserve and strengthen, not destroy it,"Schaeuble added, echoing statements from a chorus of European leaders and institutions that have urged Britain to stay.

German Chancellor Angela Merkel said on Thursday Britain would lose privileged access to the single European market if it decided to leave the EU.

French Economy Minister Emmanuel Macron warned Britain on Saturday it would become a minor trading post no more important on the world stage than the island of Guernsey if it quit.