Armenian opposition organized a 24-hour protest in Yerevan Friday to demand early elections and electoral law reform beforehand.
The Armenian National Congress, headed by former President Levon Ter-Petrosyan, called for a day-and-night long peaceful rally in central Yerevan's Freedom Square.
The opposition wants presidential and parliamentary elections before the end of the year, amendments to Armenia's electoral code, release of political prisoners and an investigation into the government crackdown on post-election protests in March 2008, which killed eight people.
The opposition has organized frequent protests since then.
The U.S. Embassy in Yerevan issued a warning for Americans in the country to avoid march routes. It says that even peaceful demonstrations can turn confrontational and escalate into violence without warning.
Deadly riots erupted in the Armenian capital, Yerevan, following the February 19th vote, when police clashed with opposition supporters who said the election was rigged. Official results gave a landslide victory to former Prime Minister Serzh Sarkisyan, who has since been sworn into office. Mr. Ter-Petrosyan won 21 percent of the vote, which he said was rigged.
More than 100 opposition members were arrested during post-election violence in 2008, and there have been allegations of police brutality against detainees.