(CNN) -- Fierce political rhetoric in Venezuela took a sharp turn Wednesday with a warning from Vice President Nicolas Maduro, who told throngs of supporters that opponents were plotting to murder him.
"We are denouncing this because we have strong evidence," Maduro said at a large rally marking the 1958 fall of Venezuela's dictatorship. "So don't get surprised with the actions we will take in the next few hours and the next few days."
It's unclear what actions he was referring to, but the Venezuelan vice president said he was committed to cracking down on "criminals who have infiltrated the country" that allegedly plan to kill him and Diosdado Cabello, the head of Venezuela's National Assembly.
Maduro's comments came as Venezuela's opposition was also rallying in Caracas on a day that has important political significance in the South American country, the anniversary of the end of Marcos Perez Jimenez's dictatorship.
President Hugo Chavez has spoken at past January 23 events, but the Venezuelan leader remains in Cuba and has not made any public appearances for more than six weeks since he underwent cancer surgery there. His long absence has fueled growing speculation about his health and political future.
Political opponents have questioned who is running Venezuela while Chavez is gone. Venezuela's government has offered conflicting assessments of the situation but maintained that Chavez is in charge.
On Tuesday, Venezuela's information minister said that Chavez was making encouraging progress, but there was no date planned for his return to Caracas.
Maduro told the crowd Wednesday that Chavez was "pressing on uphill" as he recovers from cancer surgery in Havana, Cuba.
A large picture of the president hung behind Venezuelan leaders on a stage at Wednesday's rally.
Maduro said he would head to Cuba to visit Chavez later in the day. In an incendiary speech, he called for the use of an iron fist.
"He who makes a mistake has to go to prison. He who violates the constitution and the peace of this country has to go to prison. And don't you come back crying after the fact and claiming to be political prisoners," Maduro said. "Iron fist against the conspiracy of the right. Iron fist of all the people, the government and the powers."
He accused infiltrators of a conspiracy to pit him and Cabello against each other.
"They've orchestrated a macabre and criminal plot with the purpose of killing us, something they won't be able to achieve," he said. "Their plan is to kill one of us and then blame the other for it. That's what they're planning to do."
Political rhetoric in Venezuela is often intense. On the campaign trail last year, it was not uncommon for Chavez to sprinkle speeches with insults aimed at his political rival, opposition candidate Henrique Capriles Radonski.
Before masses of supporters and in state television interviews broadcast nationwide, Chavez described Capriles as a "dirty swine" and a "fly" who was not worth chasing. He called him a "little Yankee" and assailed him as a member of the bourgeoisie.
During Chavez's absence in recent weeks, government officials have repeatedly accused political opponents of trying to destabilize the country with a campaign of rumors about the president's health.