CARACAS (AP) ― President Hugo Chavez rallied tens of thousands of supporters on Monday, wearing his signature red beret and singing a folk song as he formalized his presidential candidacy and launched his re-election bid.

Chavez waved and blew kisses to crowds as he rode atop a truck to the country’s elections office, then picked up a document registering as a candidate. Afterward, he stepped onto a stage and energetically sang along with a band to a traditional tune from the rural plains where he was born. Chavez laughed and danced briefly on stage. 

The 57-year-old leader, a former army paratroop commander first elected in 1998, is seeking another six-year term in the Oct. 7 presidential vote. His struggle with cancer has recently forced him to scale back his public appearances and has raised questions about whether his health may interfere with the re-election campaign.

“It was a difficult year,” Chavez said in a speech to cheering crowd. “Here I am, before you again!”

“We’re just warming up our engines,” he said, vowing to win the vote in a “knockout.”

As Chavez registered his candidacy, the crowd chanted: “Ooh-Ah! Chavez’s isn’t going away!”

Chavez’s supporters wore their socialist party’s red caps and shirts, holding photos of the president and signs reading: “We’re giving it our all, out of love for Chavez.” Three giant inflatable likenesses of Chavez rose above the crowd that surrounded the elections office.

On his way to the elections office, Chavez wore a track suit in the yellow, blue and red of Venezuela’s flag as he rode through streets lined with supporters. Confetti floated in the air as he passed. Some in the crowd waved flags, and others blew whistles and horns.

Chavez was accompanied by relatives including his brother Adan and two daughters.

Adela Blanco, who works at a government food processing company, said she thinks Chavez has been looking better lately despite his illness. “He has to rest. He has to recover in order to continue on,” she said.

Chavez’s rival, Henrique Capriles, led a huge crowd of supporters Sunday as he registered his candidacy, working up a sweat by marching and jogging 10 kilometers from a park in eastern Caracas to the headquarters of the National Electoral Council.

Some Venezuelan analysts have said they expect Chavez’s illness could be a point against him in the presidential campaign, especially if his condition limits his mobility and strength. Despite his illness, though, Chavez’s approval ratings have remained above 50 percent during the past year, and recent polls put him in the lead the over Capriles.

Luis Vicente Leon, who heads the Venezuelan polling firm Datanalisis, said Chavez has managed his illness in a way that has allowed him to benefit politically so far while also avoiding having the bulk of the Venezuelan population “believe it’s a deadly illness that will impede Chavez’s future.”

As the vote nears, though, Chavez will likely have to adjust his strategy to show he is well enough to campaign in order to avoid potential fallout, Leon said.

Chavez said Saturday that he has undergone tests following his cancer treatment and everything came out well.

The president returned from Cuba on May 11 after what he said was a difficult round of radiation therapy.

In the past year, Chavez has undergone two surgeries that removed tumors from his pelvic region, most recently in February. During Chavez’s yearlong cancer struggle, he has not disclosed key details about his illness including the type of cancer or the precise location of the tumors.

Both during and after his cancer treatments, Chavez has appeared in public less frequently than he used to, a dramatic shift for a leader who for much of his 13-year-old presidency has kept a busy schedule of televised talks and rallies.

While Chavez has taken a lower profile, his government has stepped up advertising that promotes his image and programs such as public housing construction. Some of Chavez’s Cabinet ministers have taken to wearing T-shirts emblazoned with a simple image showing only Chavez’s eyes.