German Chancellor Angela Merkel is blasting trade protectionism as she prepares to host the Group of 20 summit in July, arguing that countries can only weaken themselves by trying to withdraw from international competition.

Merkel told a G-20-related business gathering in Berlin on Wednesday that people may expect short-term advantages from protectionism — but "in the middle and long term their own ability to innovate is weakened, because new ideas and developments flourish best in an environment of freedom and openness."

Merkel didn't name any single person or country but pointed to the difficulty of making progress in the G-20.

She said that, for example, some are reluctant to revisit previous statements on climate change and trade — "sometimes holding on to what has been achieved is already a success."