Friedrich Merz did not rule out common European Union borrowing for defence on Friday during his first trip to Brussels as German chancellor, but said it could only be for exceptional circumstances and that he was worried about rising global debt.

The conservative politician had unexpectedly failed to secure enough support in the initial round of parliamentary voting.

Supporters of Mr. Merz, a former corporate lawyer, say he is well-prepared and thoughtful, but critics accuse him of failing to think more than one step ahead and breaking promises.