At the same time, Vice President Nicolas Maduro urged Venezuelans not to believe rumors about Chavez's health. He told Venezuelan broadcaster Telesur Chavez was "aware of the complex and delicate situation he is going through" and said Chavez had "the same strength as always" when Maduro visited him the past few days.
Maduro said Chavez squeezed his left hand "strongly" before Maduro left the hospital room.
Maduro, his wife, Attorney General Cilia Flores, and Chavez family members arrived in Havana Saturday.
Maduro, 50, told the broadcaster in the recorded interview broadcast Tuesday night Chavez told him to return to Caracas, the capital, Wednesday "to report the truth" about the 58-year-old president's condition, which he said the government has done "and will continue to do."
He didn't say what the truth was.
Sources told ABC Chavez was breathing through mechanical ventilation and being fed intravenously and rectally, and Russian doctors treating him said his kidneys were failing.
The doctors were considering ending the life support, the newspaper said.
Maduro and other Venezuelan officials have referred only to Cuban doctors treating Chavez.
ABC is considered a newspaper of record in Spain, along with El Pais and El Mundo, although it is known for generally supporting conservative political views. Chavez considers himself a socialist aligned with the communist governments of Fidel and Raul Castro in Cuba.
Venezuelan Information Minister Ernesto Villegas said earlier Tuesday Chavez congratulated the Cuban people on the 54th anniversary of Fidel Castro's Jan. 1, 1959, ouster of Cuban dictator Fulgencio Batista.
Chavez, who hasn't been seen in public since his fourth cancer-related surgery Dec. 11, suffered "new complications" after a respiratory infection and was in "delicate" health, Maduro said in a separate TV broadcast from Havana Sunday night.
Chavez declared himself fully recovered from the unspecified cancer July 9, 2012, three months before an October election in which he sought another six-year term. He warned if an opposition candidate wins the presidency, it would mean an end to social reforms and national civil war.
Chavez won his fourth term Oct. 7, defeating center-right opposition candidate Henrique Capriles, the governor of Miranda, one of the country's most populous states, which includes part of Caracas.
Before going to Cuba for his latest surgery, Chavez designated Maduro as his successor if he should prove unable to continue to lead the country.
Chavez is scheduled to be inaugurated for his third term Jan. 10.
National Assembly President Diosdado Cabello has said the swearing-in ceremony would be postponed if Chavez can't make it. But opposition leaders say postponing the inauguration would be unconstitutional.
Government officials say the constitution makes no provision for what happens if a president-elect cannot take office on inauguration day.
The constitution does say in the case of an "absolute absence" of the president, elections must be held within 30 days.
A former Venezuelan defense and foreign affairs minister who served in the 1990s under President Carlos Andres Perez, before Chavez came to power, said in a newspaper opinion piece he expected ruling party officials would do anything to stay in power, including staging a coup if an opposition candidate wins a future presidential election.
"They may try to flagrantly violate the constitution by using one of the many legal tricks that they have used, or if not possible this way, simply by using stark force," Fernando Ochoa Antich said in Venezuela's El Universal newspaper.
"The ethical justification is the same as always -- to preserve the revolution, as if that word would justify all the abuses of power that the ruling clique has submitted Venezuela to since achieving power," he wrote.
In supporting his argument, Antich quoted Cabello as saying Dec. 26 Venezuela's rulers would defend their power "with our knee on the ground, arms on our shoulders and bayonets cocked." And he quoted Defense Minister Diego Molero Bellavia as saying Dec. 24 the armed forces "already know what to do -- to be fully prepared for the purposes of continuing the path set ideologically 14 years ago by the leader of the Bolivarian revolution."