Developing nations at the Brics summit on Monday brushed away an accusation from US President Donald Trump that they are "anti-American," with Brazil's president saying the world does not need an emperor after the US leader threatened extra tariffs on the bloc.

Trump's threat came as the US government prepared to finalise dozens of trade deals with a range of countries before his July 9 deadline for the imposition of significant "retaliatory tariffs."

The Trump administration does not intend to immediately impose an additional 10 percent tariff against Brics nations, as threatened, but will proceed if individual countries take policies his administration deems "anti-American," according to a source familiar with the matter.

At the end of the Brics summit in Rio de Janeiro, Luiz Inacio Lula da Silva was defiant when asked by journalists about Trump's tariff threat: "The world has changed. We don't want an emperor."

"This is a set of countries that wants to find another way of organising the world from the economic perspective," he said of the bloc.

"I think that's why the Brics are making people uncomfortable."

In February, Trump warned the Brics would face "100 percent tariffs" if they tried to undermine the role of the US dollar in global trade.

Brazil's Brics presidency had already backed off efforts to advance a common currency for the group that some members proposed last year.

But Lula repeated on Monday his view that global trade needs alternatives to the US dollar.

"The world needs to find a way that our trade relations don't have to pass through the dollar," Lula told journalists at the end of the Brics summit in Rio de Janeiro.

"Obviously, we have to be responsible about doing that carefully. Our central banks have to discuss it with central banks from other countries," he added.

"That's something that happens gradually until it's consolidated."

Other Brics members also pushed back against Trump's threats more subtly.

South African President Cyril Ramaphosa told reporters that the group does not seek to compete with any other power and expressed confidence in reaching a trade deal with the US.

"Tariffs should not be used as a tool for coercion and pressuring," Mao Ning, the Chinese foreign ministry spokesperson said in Beijing.

The Brics advocates for "win-win cooperation," she added, and "does not target any country."

A Kremlin spokesperson said Russia's cooperation with the Brics was based on a "common world view" and "will never be directed against third countries." (Reuters)