Brazil's Federal Police are investigating possible US interference in the country's presidential election after receiving a complaint from the Attorney General's Office, the agency's director general said Sunday as voting got underway nationwide.

"This is an investigation underway, a preliminary procedure. The inquiry has not yet been formally published, but we already have an investigation in progress," Federal Police chief Andrei Rodrigues told reporters in the capital Brasilia.

Rodrigues said the case had been forwarded to the agency's Intelligence Directorate for analysis as Federal Police worked to ensure the smooth running of the 2026 elections.

The request from the Attorney General's Office seeks an investigation into possible foreign interference in Brazil's electoral process.

It was based on a report by British newspaper The Guardian alleging that US government funds were redirected to networks and organizations in Brazil. According to the Brazilian government's filing, the funds were allegedly used to interfere in political debate and "destabilize and attack the institutional framework of Brazil's judiciary," the Agencia Brasil news agency reported.

Election underway as candidates cast votes The probe comes as Brazilians vote in a closely watched presidential election led by incumbent President Luiz Inacio Lula da Silva and Sen. Flavio Bolsonaro, the son of former President Jair Bolsonaro. Both leading candidates cast their ballots during the first hours of voting.

"I am very confident, not only because of the government we have built, but also because of the work we did during the campaign. I am sure we will have a very high turnout, and I am sure we will win this election," Lula told reporters after voting.

Lula, seeking a fourth nonconsecutive term, cast his ballot in Sao Bernardo do Campo, in Sao Paulo state, around 9.15 a.m. local time (1215GMT).

He was accompanied by Vice President Geraldo Alckmin and other political allies. Flavio Bolsonaro voted in Rio de Janeiro shortly after polls opened.

He also predicted a first-round victory, saying he wanted to "restore to Brazilian families the right to dream again." Polling stations opened nationwide at 8 a.m. Brasilia time and are scheduled to close at 5 p.m., with nearly 159 million voters eligible to participate in the first round, according to Brazil's Superior Electoral Court, or TSE.

Polls show tight presidential race The latest Datafolha poll published Saturday put Lula at 45% and Flavio Bolsonaro at 42% of valid votes, with both below the 50% threshold needed to avoid a runoff. The Organization of American States electoral observation mission said voting was proceeding smoothly and under adequate safety conditions.

Federal Police said 48 people had been detained over suspected electoral crimes, including alleged vote buying and irregular campaigning.

Authorities also reported technical incidents involving electronic voting machines.

In the southern state of Santa Catarina, the regional electoral court reported 99 incidents during the morning, with 46 machines replaced by backup equipment. Rodrigues also addressed concerns surrounding diplomatic missions after the US and Australian embassies temporarily suspended consular services Friday, citing security reasons.

"We did not find any concrete element indicating an effective risk to any embassy. The elements collected yesterday do not point to anything concrete or to the existence of any plan that we have identified," he said.

Partial overseas counts for the presidential election have begun in time zones where voting has already ended.

Nearly 919,000 Brazilians areed to vote abroad. The TSE said counting will begin at 5 p.m.

Brasilia time, with results released progressively as voting-machine records are received and processed.

If no presidential candidate receives more than half of the valid votes, a runoff will be held Oct. 25. Voters are also choosing governors, senators, members of the Chamber of Deputies and state or district lawmakers.