Venezuela’s political opposition has vehemently rejected the electoral authority’s ruling that Nicolas Maduro was reelected as the nation’s president, calling on the military to intervene. The U.S. and some Latin American neighbors also raised concerns about the official result.

Maduro won Sunday’s election with 51.2% of the vote, compared with 44.2% for rival Edmundo Gonzalez, the electoral center said. But opposition leader Maria Corina Machado said that her coalition had gained access so far to 40% of the tabulated votes and had Gonzalez winning 70% of the vote so far.

An exit poll conducted by U.S. firm Edison Research also had Gonzalez winning by more than 30 percentage points, lending to suspicions that Maduro’s administration had tampered with the tally.