CARACAS - Venezuela's ever-theatrical President Hugo Chavez made a surprise homecoming on Monday after cancer surgery in Cuba, thrilling supporters with an emotional pledge to win the fight to regain his health.

His voice straining at times, Chavez told a crowd of thousands gathered outside the Miraflores presidential palace in Caracas he still needed strict medical treatment.

Venezuela's President Hugo Chavez greets supporters while appearing on a balcony of Miraflores Palace soon after his return to the country from Cuba, where he underwent surgery and treatment for cancer, in Caracas July 4, 2011. [Photo/Agencies]

"Let nobody think my presence here today, July 4, means that we have won," he said.

"I swear that we will win the battle".

After an overnight flight home, Chavez, 56, rested during the day then appeared on the balcony where he has addressed the nation during some of the biggest moments of his rule, including after he survived a short-lived 2002 coup.

Chavez's return changes the political dynamics once again in Venezuela, where politicians on all sides had been bracing for a protracted months-long absence of the man who has dominated the OPEC member nation since taking power in 1999.

"Long live life, long live Chavez!" the president, wearing a military uniform, told his delirious fans. He was strong enough to sing the national anthem and talk for 34 minutes.

Some supporters wept as Chavez recounted details of his operation in Cuba. "Those days were not easy," he said.

Before speaking from the balcony, Chavez waved a large Venezuelan flag and made the Christian sign of the cross.

With their "comandante" back on Venezuelan soil, elated supporters took to the streets of Caracas all day, chanting: "He's back! He's back!" and "Ooh! Aah! He's here to stay!"

Lengthy treatment possible

Many Venezuelans had thought Chavez's convalescence after two operations last month in Cuba - one to remove a cancerous tumor - would keep him in Havana for weeks, possibly months.

"I'm fine. I feel well," Chavez said upon arrival, singing a folk song and hugging ministers at the airport.

"I'm back at the epicenter of Bolivar," he added, in reference to his idol, Simon Bolivar, a hero of South America's fight for independence from Spanish rule.

Despite euphoria among supporters, Chavez's exact condition is unclear. He may still face lengthy treatment, throwing into question his ability to prepare for a 2012 re-election bid.

Chavez said his homecoming was "the start of the return," implying to some he may keep a low profile in Venezuela or even return to Cuba for further cycles of treatment.

Chavez's return caught Venezuelans by surprise on the first of two days of holidays for Tuesday's independence date.

"He's looking a bit better. May God take care of him and cure him," said 65-year-old pensioner Berxi de Chavez at the rally outside the presidential palace.