The US State Department announced that it had revoked the visa of Brazil’s Ambassador to Washington, Maria Luiza Ribeiro Viotti, under the principle of reciprocity. Officials said the move was a response to Brazil’s refusal to grant visas to two American diplomats and its delaying the confirmation of the new US ambassador nominated by President Donald Trump.
US State Department officials speaking to the Associated Press (AP) said that the Washington administration postponed the decision several times to give Brazilian President Luiz Inacio Lula da Silva time to take the necessary steps, but implemented it when the expected steps did not materialize. The officials also stated that the decision could be quickly reversed if Brazil takes appropriate steps and approves the ambassador nominated by Trump. They stressed that Ambassador Viotti was not expelled from the US.

How did the tensions in relations escalate?
The diplomatic crisis between the two countries started when Brazilian authorities decided to delay the confirmation of Danny Perez, Trump’s nominee for the US Embassy in Brazil, until after the elections set for October 4.
Brazil also refused last month to issue visas to Riley Barnes, a Deputy Assistant Secretary in the US State Department's Bureau of Democracy, Human Rights, and Labor, and a senior aide, following reports that the American diplomats might criticize President Lula or the election process.
The US State Department denied these allegations, emphasizing that the planned visit of the two diplomats on July 27-30 to discuss election integrity, religious freedom, and freedom of expression was a routine working visit. Washington also dismissed as baseless the claims that it was a "plan to sabotage elections in a democratic country."