Top senators from President Joe Biden's Democratic Party warned Tuesday that the US relationship with Brazil would be at risk if President Jair Bolsonaro does not respect democratic norms in October 2022 elections.

The far-right leader, one of the leading international allies of Donald Trump, has warned that Brazil could see scenes reminiscent of the January 6 mob violence in Washington by supporters of the former US president's false claims of election fraud.

In a letter to Secretary of State Antony Blinken, four Democratic senators said that disruption in Brazil's democracy "would jeopardize the very foundation" of relations between the Western Hemisphere's two most populous nations.

"We urge you to make clear that the United States supports Brazil's democratic institutions, and that any undemocratic break with the current constitutional order will have serious consequences," said the senators including Dick Durbin, the chamber's number two Democrat, and Bob Menendez, chairman of the Senate Foreign Relations Committee.

Brazilian President Jair Bolsonaro, seen in Brasilia in September 2021, has faced criticism from US Democrats over his comments on democracy
Brazilian President Jair Bolsonaro, seen in Brasilia in September 2021, has faced criticism from US Democrats over his comments on democracy AFP / EVARISTO SA

The senators voiced alarm at Bolsonaro's claims without evidence that the voting system is mired in fraud and his suggestions that he would not concede defeat.

"This type of reckless language is dangerous for any democracy, but it is especially unmerited in a democracy of Brazil's caliber, which for decades has shown itself capable of facilitating peaceful transfers of power."

The Biden administration has been low-key in public statements on Bolsonaro, and Blinken met last week on the sidelines of the UN General Assembly with Brazilian Foreign Minister Carlos Franca.

A State Department official said the meeting was largely to encourage the climate-skeptic Bolsonaro to raise ambitions ahead of a high-stakes UN climate conference in Glasgow in November, with Brazil a crucial player for the planet due to the Amazon's role as a carbon sink.

Bolsonaro, whose approval rating has tanked in part due to Brazil's severe Covid-19 outbreak, has said he will not stage a coup although some supporters have called on the military to intervene to keep him in power.