Venezuelan media reported on Sunday a shootout that killed two at the sidelines of Venezuela's presidential election, as well as a series of minor incidents that are unlikely to affect the final outcome.

Newspaper El Universal reported a shootout close to a polling station in Tacarigua, in northern Miranda state, between armed men on motorbikes. However, it did not say whether the incident was linked to political disputes.

Separately, a top military official said security on the streets of Venezuela was reinforced Sunday as voters went to the polls in the most contested presidential election in the past 14 years.

Wilmer Barrientos, head of the Strategic Operational Command of the National Bolivarian Armed Forces, said "we are stepping up patrols ... to be able to resolve any problems that may arise."

Barrientos made the remark after delivering a report on the progress of the election, saying the homicides were apparently unrelated to the day's electoral events.

"Unfortunately, there have been shooting deaths, but they have nothing to do with the electoral process," Barrientos said.

During elections, the agency under his command executed a so- called Plan of the Republic to safeguard the security of voters, candidates and electoral officials. As part of the plan, some 139,000 troops were stationed throughout the country, 8 percent more than in the 2006 presidential election, when 128,900 troops were mobilized.

Venezuelan President Hugo Chavez won the 2006 election, his second, with more than 60 percent of the votes, but this year's race against opposition candidate Henrique Capriles was expected to be tighter.

Some 19 million Venezuelans at home and 100,000 overseas were registered to elect a president who will serve a six-year term starting January 2013. Polling began at 6 a.m. local time (1030 GMT) and is set to close at around 6 p.m. local time (2230 GMT).

Also on Sunday, observer organization Education Assembly Election Watchdog Network (ROE-AE) reported five irregularities across the 567 polling stations it covers.

They included late opening of polling stations, an excess of spoiled votes, slowness in replacing broken voting machines and a lack of support from electoral officials. These affected 20 of the 567 polling stations, it said.

One such case was that of Las Palmas, an upscale Caracas neighborhood, where voting machines broke down an hour after polling began, and were not replaced. Only 35 people were able to vote at the site.

Sandra Oblitas Ruzza, vice president of the National Electoral Council (CNE), which runs Venezuela's elections, told media that the CNE has ordered polling stations to speed voters through the process to balloting when it is clear that they have come to the right place, to prevent the buildup of queues.

"This has been an excellent process, following all the rules," Oblitas told a press conference. "The reports of null votes do not represent a significant amount. But it is important that there is no generation of false information. Where a voting machine has produced a null vote, citizens can vote again."

When citizens vote, the voting machine produces a paper ticket with details of the vote, meaning that officials can recall mistaken data before it is processed.

ROE-AE observers told media that even with the incidents they recorded, nearly 98 percent of polling stations were running correctly by 9 a.m. and that 99 percent of all polling stations had observers from the country's two major coalitions: the Great Democratic Pole, which is fielding incumbent Hugo Chavez as its candidate; and the Democratic Unity Roundtable, which is fielding Henrique Capriles. The CNE estimates that 75 percent of registered voters will participate. The council said in an official statement that it will begin publishing results late Monday when counting begins to show an "irreversible" trend.