Fidel Castro upped the ante in the row between the United States and Venezuela on Tuesday when he warned that the government of embattled President Nicolás Maduro was prepared to confront U.S. "threats and impositions," Agence France-Presse noted.

In a letter published in Granma, the mouthpiece of Cuba's Communist Party, the revolutionary leader praised the "attitude of the heroic people of (independence leader Simón) Bolívar and (former President Hugo) Chávez."

Venezuela "has declared in a precise fashion that it has always been ready to hold talks with the government of the United States in a peaceful and civilized fashion, but it will never accept that country's threats and impositions," the 88-year-old insisted.

The former Cuban president, who handed over the reins to his younger brother, Raúl, in 2008, has been outspoken on Venezuela despite recent attempts by Washington and Havana to mend ties after the 50-year U.S. embargo against the Caribbean nation.

The Washington Post noted this month that the fact that the most visible displays of support for Maduro came from Fidel -- and not Raúl -- was "telling."

"While Raúl Castro also regularly pledges to support the Venezuelan president, he does not have the same close personal relationship" with Maduro, the newspaper explained. Fidel Castro is also known to have been a close friend of Chávez's, Maduro's late predecessor.

In his Granma letter, the elder Castro also warned that Venezuela today has the "best equipped army in Latin America," El Universal noted.

"No matter what U.S. imperialism may do, it will no longer count on (Venezuelan soldiers) to do what it did for so many years," he wrote. "Today, Venezuela has the best equipped soldiers and officers" in the continent, Castro added.

Castro's comments seem to be an allusion to military cooperation between the United States and Venezuela in the pre-Chávez era. Since 2004, Caracas is no longer allowing its personnel to train at the Georgia-based Western Hemisphere Institute for Security Cooperation -- better known as the School of the Americas.

"When you met with (Venezuelan) officials in recent days, you could see they were ready to give the last drop of their blood for the country," the Cuban leader noted in his missive.