Argentina and Venezuela are feuding over the release of political prisoners.

During a meeting of the Mercosur sub-regional trade bloc in Asunción, Paraguay, Argentine President Mauricio Macri urged South American leaders to support the release of jailed political heads, BBC reported. The United Nations, the European Union, and the United States government have also pressured Venezuela over the issue.

"Venezuela's government must work toward achieving a true culture of democracy for our region," Macri remarked, as quoted by the Guardian. "There can be no place for ideological persecution in Mercosur member states."

Venezuela's government has denied holding political prisoners, but the imprisonment of numerous high-profile opposition leaders such as former mayors Leopoldo López and Antonio Ledezma has sparked criticism from human rights groups, including the U.N., the E.U., and the U.S., the news outlet listed.

In September, López was sentenced to almost fourteen years in jail on charges of provoking violence during anti-government protests in 2014, which resulted to the deaths of 43 people, BBC wrote.

Macri underlined his commitment to the issue by taking a picture on the night of his presidential election on Nov. 22 with Lilian Tintori, the wife of López, the Guardian noted. Before the Argentine leader took office on Dec. 10, he pushed for Venezuela to be removed from Mercosur for violating its "democracy clause," the Guardian added.

According to the Guardian, Venezuela's suspension from the Mercosur was derailed when Venezuelan President Nicolás Maduro's government respected the results of the Venezuelan congressional elections on Dec. 6. Mercosur members said that the suspension would only push through if Venezuela refused to accept the voting results and severed the group's so-called democratic clause, which indicates that a member country can be sanctioned if it has broken the democratic order.

In response to Macri's cause, Venezuelan Foreign Minister Delcy Rodriguez accused Argentina of failing to bring justice to those who had committed human rights abuses during the military government of the 70s and 80s, BBC further reported. Maduro wasn't in attendance at the Mercosur summit.

Rodríguez defended Venezuela's socialist government and accused Macri of interfering in her country's internal affairs, the Guardian noted.

"Macri is defending the political violence of 2014, when [opposition demonstrators] used bazookas, set the public ministry on fire," Rodríguez said of the 2014 protests in Venezuela, as quoted by the news outlet.

Venezuela became a full member of the South American bloc in 2012 in order to unite the region's most powerful agricultural and energy markets, the Guardian added.