YANGON (Reuters) - Myanmar held its first election in 20 years on Sunday under tight security, a scripted vote that assures army-backed parties an easy win but brings a hint of parliamentary politics to one of Asias most oppressed states. The carefully choreographed end to half a century of direct army rule is largely a race between two military-backed parties running virtually unopposed, due to complex election rules that stifled any prospect of pro-democracy forces causing an upset. Low turnout and fraud charges marred voting nationwide. Many doubted their ballot would alter the authoritarian status quo. Some packed Yangons pagodas instead of voting. In Haka, capital of Chin state bordering India and Bangladesh, more people attended church than cast ballots, witnesses said. Were falling asleep, said a polling station official in Bahan Township in the commercial capital Yangon. Ward officials are still urging the people to vote. The poll will not bring an end to Western sanctions but may reduce Myanmars isolation at a time when neighbouring China has dramatically increased investment in natural gas and other resources in the former British colony also known as Burma. Armed riot police stood guard at polling booths or patrolled streets in military trucks in Yangon, part of a security clampdown that includes bans on foreign media and outside election monitors, and a tightening in state censorship. The Internet was barely functioning, hit by repeated failures widely believed to have been orchestrated by the junta to control information. Power failures also hampered early turnout. It is the first election since 1990, when Nobel laureate Aung San Suu Kyis National League for Democracy beat the army-backed party in a landslide. The junta simply ignored that result. Suu Kyi, detained for 15 of the past 21 years, urged a boycott of this poll, saying she would not dream of taking part. She could take the spotlight this week, however, ahead of the expiry of her house arrest on Saturday, November 13. Her release could energise pro-democracy forces and put pressure on the West to roll back sanctions. The juntas political juggernaut, the Union Solidarity and Development Party (USDP), is fielding 27 incumbent ministers. Closely aligned with supreme leader Senior General Than Shwe, it is top-heavy with recently retired generals. It is contesting all the estimated 1,158 seats up for grabs. Its only real rival, the National Unity Party (NUP), is also backed by the army and running in 980 seats. But while the NUP and USDP are both conservative and authoritarian, they may pursue opposing social and economic policies in parliament, ultimately fostering greater democratic debate in a country where an estimated 2,100 political activists and opposition politicians are behind bars, diplomats said. An unexpectedly large vote for the NUP could also be seen as a subtle jab against Than Shwe, as it is thought to be closer to a different faction in the army. They are not of the same machinery, a Western diplomat said of the two dominant parties, citing tensions between the two on the campaign trail. The USDP is very much the regimes party while the NUP has a longer legacy, he added, referring to its founding under the rule of late dictator Ne Win. Ne Win was placed under house arrest in 2002 by Than Shwe, who accused him of treason. Ne Win died that year. Despite such differences, the military will emerge the unquestioned winner. Twenty-five percent of seats in all chambers are reserved for serving generals. That means army-backed parties needs to win just 26 percent of seats for the military and its proxies to secure a majority in the legislature. But the army appears to be taking no chances. At least six parties lodged complaints with the election commission, claiming state workers were forced to vote for the USDP in advance balloting. In Yangon, many voters turned up to vote only to find their names not on electoral rolls, said Zaw Aye Maung, a candidate for the Rakhine Nationalities Development Party, the second-largest of 22 ethnic-based parties. Hundreds of Rohingyas, a stateless Muslim minority in Myanmar, were given identification cards in Yangon and the right to vote in exchange for backing the USDP, he added. Some voters who asked officials for assistance at ballot booths were told to tick the box of the USDP, witnesses said. The National Democratic Force (NDF), the largest pro-democracy party, accused the USDP of widespread fraud. Thirty-seven parties are contesting places in a bicameral national parliament and 14 regional assemblies. Except for the USDP and NUP, none has enough candidates to win any real stake due to restrictions such as high fees for each candidate.