Official results in Bolivia with 95 percent of the vote counted Tuesday showed 52 percent of voters rejecting President Evo Morales' bid to change the constitution so he can run for a fourth consecutive term in 2019.

That margin of defeat agreed with a "quick count" unofficial vote sample from Sunday' referendum done by the Ipsos-Apoyo firm, which sampled one in 15 voting stations.

The vote count had been unusually slow and Vice President Alvaro Garcia said the election would be a "cliff-hanger."

He claimed a right-wing conspiracy was "trying to make disappear by sleight of hand the rural vote that favors Morales." Garcia provided no evidence to back the claim.

Organization of American States observers reported no evidence of fraud, as some in the opposition claimed. The delegation issued a statement calling for calm and reminding Bolivians that official channels exist for filing complaints. The delegation's leader, former Dominican Republic President Leonel Fernandez, left Bolivia on Tuesday.

The president of the Supreme Electoral Tribunal in charge of the vote count, Katia Uriona, said results were still coming in from six of Bolivia's nine states.

Tribunal member Jose Luis Exeni said heavy rains in some rural areas had delayed the arrival of some results in state capitals, where they are tallied before being sent electronically to Sucre, where the tribunal is based.

Government transparency in the vote count has been questioned.

The results page on the electoral tribunal's website has often been inaccessible. And the electoral council inexplicably dropped a consolidated count that combined domestic votes with those cast abroad.

Calls to electoral tribunal officials seeking an explanation were not answered.