The only independent observer monitoring the polls in Venezuela said that Sunday’s vote for president did not meet international standards and was undemocratic, raising more questions about the legitimacy of the results.
The mission, led by the Carter Center, a pro-democracy organization, said late Tuesday that the election violated Venezuela’s own laws and the government’s failure to release a vote count was a “serious breach of electoral principles.”
The group joined the United States and many other countries that have said Venezuela’s election was marred by irregularities. At least 16 people have been killed in protests that erupted after election officials declared the country’s autocratic leader, President Nicolás Maduro, the winner.
The condemnation by the Carter Center, which was the lone independent election monitor the government allowed into Venezuela ahead of the vote, came hours after opposition leaders announced updated election results, which they said showed Mr. Maduro received less than a third of votes cast.
Venezuelans went to the polls Sunday to choose between Mr. Maduro, who has been in power since 2013, and Edmundo González, a former diplomat who served as a stand-in for María Corina Machado, a more popular opposition leader who had been barred by the government from running.
Ms. Machado released data showing that with more than 81 percent of the machines counted, Mr. González received 67 percent of the vote, compared with 30 percent for Mr. Maduro. The opposition’s count came from voting machine tallies provided to election observers, which they scanned and calculated, she said.
The government-controlled election authority said Mr. Maduro had received 51 percent of the vote, and Mr. González 44 percent. But the authority has yet to provide voting data, and critics say the body essentially expected that the nation would take its word that Mr. Maduro won another six years in office.
On Wednesday President Gustavo Petro of Colombia, a leftist like Mr. Maduro who had made drawing Venezuela closer a priority early in his administration, expressed serious doubts about the results in his first public statement about Sunday ’s vote.
“The grave doubts that have arisen around the Venezuelan electoral process can lead its people to a deep violent polarization with serious consequences,” Mr. Petro wrote on X.
“I invite the Venezuelan government to allow the elections to end in peace, allowing a transparent vote count.”
As the president of a bordering nation, Mr. Petro has a vested interest in the outcome: millions of Venezuelans have left the country on foot for Colombia. Pressure had been mounting inside Colombia for Mr. Petro to say something.
Mr. Maduro was clearly annoyed. He said at a news conference on Wednesday at the presidential palace that Colombia was the “epicenter” of the conspiracy against him and stressed that he never meddled in that country’s business.
The Carter Center, which is based in Atlanta and was founded by former President Jimmy Carter, has observed more than 100 elections around the world and sent a delegation of 17 people to Venezuela. They met with the elections council, the candidates, political parties, the armed forces and other interested groups.
The Venezuelan election “cannot be considered democratic,” the Carter Center said in a statement late Tuesday. “The Carter Center cannot verify or corroborate the results of the election.’’
The Carter Center’s statement is noteworthy because, in the past, Mr. Maduro has often cited the number of observers present to prove that elections were fair.
José Ignacio Hernández, a senior associate at the Center for Strategic and International Studies, said the statement could sow division among the leadership of the Maduro regime, some of whom may not have been on board with the government’s actions.
“Maduro will dismiss the report,” Mr. Hernández said, “but Maduro invited the Carter Center, and the defense minister had praised the labor of the Carter Center.”
José R. Cárdenas, a former Bush administration official who follows Venezuela closely, said the statement was important, because the Carter Center had defended Venezuela’s electoral system after a 2004 recall referendum failed to oust Hugo Chávez, Mr. Maduro’s predecessor as president and his longtime mentor.
In 2012, Mr. Carter called Venezuela’s electoral process, which had undergone significant improvements, “the best in the world.”
“They have now done a 180,” Mr. Cárdenas said.
Mr. Maduro, during the news conference, accused Carter Center of not questioning the last U.S. election, after it was contested by former President Donald J. Trump.
“Everyone who came here to Venezuela from the Carter Center came here with the report already written,” Mr. Maduro said.
While there were other election observers in Venezuela, they are friendly to Mr. Maduro and not considered impartial, analysts said.
The United Nations sent a panel of experts to Venezuela, but it was not an official observation mission, and its report has not been made public.
But Volker Türk, the U.N. High Commissioner for Human Rights, said on Tuesday that he was “alarmed by reports of disproportionate use of force by law enforcement officials.”
Mr. Maduro said Mr. Turk was either “badly misinformed” or “malicious.” “He says whatever the gringos tell him to say,” he said.
After summoning journalists to the palace, Mr. Maduro, who spoke for two hours, excoriated the international media, blaming it for sowing violence. He said a hack of the voting system along with vandalism to various of its buildings amounted to a “coup against the electoral system.”
“Venezuela has its truth,” he said, “and I came here to defend the truth.”
He also defended the government’s refusal to release the vote count, claiming that the country’s Supreme Court would ultimately have to make that decision. Yet, experts noted, that has not been the practice in past elections, and the high court is aligned with Mr. Maduro and has already congratulated his victory on Sunday.
Human rights groups, government officials and family members of victims said that 16 people, including one soldier, had died amid protests. Penal Forum, a human rights organization, tallied 11 deaths, but The New York Times identified at least four more cases at a Caracas morgue.
“They are young people who were simply protesting,” said Alfredo Romero, the group’s president.
Ms. Machado said at least 177 opposition activists had been arrested “arbitrarily.”
John F. Kirby, a White House spokesman, said the Organization of American States would address Venezuela’s election later on Wednesday.
“Our patience, and that of the international community, is running out,” Mr. Kirby said. “It’s running out on waiting for the Venezuelan electoral authorities to come clean and release the full, detailed data on this election so that everyone can see the results.”
In Caracas, security forces, according to opposition leaders, had surrounded the Argentine Embassy, where several members of Ms. Machado’s campaign facing arrest warrants have been holed up for months.
The Venezuelan government has threatened to arrest opposition leaders after accusing them of inciting violence. Jorge Rodríguez, Mr. Maduro’s campaign chief and the national assembly leader said he hoped that Ms. Machado and Mr. González would be arrested soon.
“I am not only referring to María Corina Machado, who has to go to jail,” Mr. Rodríguez said on Tuesday. “I am referring to Edmundo González Urrutia, because he is the head of the fascist conspiracy that they are trying to impose in Venezuela.”
The attorney general’s office in Venezuela did not respond to a request for comment about whether any criminal charges were being pursued.
Summoned by the president, several hundred supporters of the government gathered in downtown Caracas on Wednesday afternoon, banging on pots and pans.
María Prieto, 44, said she had come out to “defend the Bolivarian revolution,” a reference to the movement started by Mr. Chavez, the former president.
“My people and I voted in favor of Nicolás,” said Ms. Prieto, who is a member of an Indigenous community. “Before the arrival of the revolution, we didn’t have rights. They didn’t even count us in the census to see how many Indigenous people were in this country.”
Aris Ferrer, 62, a university professor, said Ms. Machado should just accept that her candidate lost.
“It does not seem right to us,” she said, “that they want to burn down a country.”
Genevieve Glatsky and Julie Turkewitz contributed reporting from Bogotá, Colombia, and María Victoria Fermín and Anatoly Kurmanaev contributed reporting from Caracas.