Berlin, Jun 30 (IANS): Without calling him by name, German Chancellor Angela Merkel offered a scathing criticism of US president Trump's policies in a speech before the Federal Parliament.

Speaking a week before the official commencement of the G20 summit in Hamburg, Merkel on Thursday emphasized Germany's commitment to multilateral cooperation to confront transnational challenges such as climate change, Xinhua news agency reported.

"Whoever thinks that the problems of this world can be solved with isolationism and protectionism is making an enormous mistake" Merkel said. "Only together can we find the right answers to the central questions of our times."

Merkel's speech contained several thinly-veiled swipes at Trump.

Addressing the issue of climate change, she warned that "we cannot and will not wait until the last person on Earth is convinced of the scientific evidence of climate change. In other words: the [Paris] climate accord is irreversible and non-negotiable."

Since the US abandoned the Paris accord, Germany was "more committed than ever to making it a success," she said.

The speech highlighted a growing discrepancy between Berlin and Washington's positions on a several international issues since Trump took office in January, ranging from climate change to trade.

Germany will host the G20 summit on July 7-8 in the Northern German city of Hamburg. Merkel wants the summit to send a "signal of determination" of the world's 20 largest industrialized and emerging nations to assume their international responsibility.