The election commission of Venezuela says President Nicolas Maduro has won a third term in Sunday's election even as the opposition claims victory. Tensions are rising between supporters of both camps.

Presidential election voting took place in the South American country on Sunday, and vote counting has begun.

The commission announced on Monday that with 80 percent of the ballots counted, Maduro won 51.2 percent of the votes.

It also said Edmundo Gonzalez, a former diplomat fielded by the main opposition parties, won 44.2 percent.

The incumbent president Maduro declared victory at a rally in the capital Caracas. He told his supporters that he will give his whole life to carry out all the changes and transformation their homeland needs.

Opposition parties say their survey shows that Gonzalez scored a landslide victory by winning about 70 percent of the votes, while Maduro won about 30 percent.

Experts had expressed concern that the election will not be fair, because the commission is under the influence of the president.

The opposition camp argues that some of its members who were due to monitor the vote counting process were denied access.

There have been reports of clashes between supporters of the two candidates in Caracas.