No credible international observers will be present to monitor Venezuela's Dec. 6 legislative elections, and observers worry about an increasingly volatile situation in the oil-rich South American nation while a top U.S. official predicted that Venezuelans are at a "dramatic crossroads."

The coalition surrounding embattled President Nicolás Maduro's United Socialist Party of Venezuela might well lose its majority in the election, a result that would mark the first serious challenge to the rule of the political heir of late socialist leader Hugo Chávez, the Washington Post reported.

"Chavismo expected it would be the dominant political force for decades, but it has discovered that in democratic societies, people hold leaders to account," the unidentified American official explained. "Ideology and the image of Chavez isn't enough to maintain a hold on power."

The leading polls ahead of the vote, meanwhile, suggest that Maduro's party will suffer steep losses, but no international experts will be on hand to monitor the voting process and provide a credible analysis of possible charges of fraud. That is because the Carter Center closed its local offices in August and because Maduro has rejected an Organization of American States mission.

Maduro has long accused the United States of trying to meddle in Venezuela's internal politics, as well as the current electoral process, and on Friday accused Washington of trying to misrepresent the death of a popular opposition leader of was killed days before the vote in central Guarico state, according to the Guardian.

Luís Diaz, a leader of the Democratic Action party, was slain in a shooting during a public meeting, an incident that drew almost immediate international condemnation from the South American regional bloc UNASUR and the U.S. government.

But Maduro said that initial investigations suggest a local gang dispute was to blame for the violent event and that the opposition was merely trying to exploit the case in order to discredit his government.