Developing nations at the BRICS summit on Monday brushed away an accusation from President Donald Trump that they are "anti-American," with Brazil's president saying the world does not need an emperor.

Trump said the U.S. will impose an additional 10% tariff on any countries aligning themselves with the "Anti-American policies" of the BRICS group of developing nations, whose leaders kicked off a summit in Brazil.

Leaders of the BRICS group of emerging economies meeting for their annual summit had hoped to downplay any differences with the U.S. But even a toned down group proclamation drew the ire of President Trump.