Updated

The leader of Chancellor Angela Merkel's center-right party is warning that Germans risk ending up with a left-wing government if they vote for the Greens, who surged in last month's European Parliament election and are now level with or ahead of Merkel's Union bloc in several polls.

The Greens traditionally leaned left but in recent years have formed regional coalitions with Merkel's Christian Democratic Union in several states. Last week, however, they rejected the chance to do so in Germany's smallest state, Bremen, and opted for a coalition with the center-left Social Democrats and the hard-left Left Party.

CDU leader Annegret Kramp-Karrenbauer told Sunday's Bild am Sonntag newspaper that "people who dream of a new government and vote Green must know that they could wake up with the Left Party."