Venezuelans vote in tense election challenging Maduro's grip on power

Polls suggest that Sunday's presidential election in Venezuela could bring an end to President Nicolas Maduro's 25-year grip on power. Tensions are high as the opposition has warned of possible irregularities and the incumbent has threatened a "bloodbath" if his challenger Edmundo Gonzales Urrutia is elected, drawing condemnation from world leaders including Brazil's Luiz Inacio Lula da Silva.