BERLIN, Jan 8 (Reuters) - German President Frank-Walter Steinmeier has strongly criticised the U.S. foreign policy under President Donald Trump and urged the world not to let the world order disintegrate into a "den of robbers" where the unscrupulous take what they want.

In unusually strong remarks, which appeared to refer to actions such as the ousting of Venezuela's President Nicolas Maduro at the weekend, the former foreign minister said global democracy was being attacked as never before.

Although the German president's role is largely ceremonial, his words carry some weight and he has more freedom to express views than politicians.

Describing Russia's annexation of Crimea and the full-scale invasion of Ukraine as a watershed, Steinmeier said the U.S. behaviour represented a second historic rupture.

"Then there is the breakdown of values by our most important partner, the USA, which helped build this world order," Steinmeier said in remarks at a symposium late on Wednesday.

"It is about preventing the world from turning into a den of robbers, where the most unscrupulous take whatever they want, where regions or entire countries are treated as the property of a few great powers," he said.

Active intervention was needed in threatening situations and countries such as Brazil and India must be convinced to protect the world order, he said.

(Reporting by Madeline Chambers; Editing by Alison Williams)