The only election debate between the leaders of Germany's two main parties - the Social Democratic SPD and the Christian Democratic CDU - has ended without a clear winner.

Opinion polls conducted by the ARD and ZDF television channels suggested SPD leader Frank Walter Steinmeier did slightly better, but a poll conducted by the RTL television channel indicated CDU Chancellor Angela Merkel was the winner.

Foreign Minister Steinmeier is currently foreign minister in Ms Merkel's cabinet, but the chancellor has indicated she wants to form a coalition with the conservative Free Democratic Party. Ms Merkel's Christian Democratic CDU has a clear lead in the polls. The elections are scheduled to be held in two weeks.