Armenians have started voting in landmark legislative elections for the first time since the adoption of constitutional reforms.
The vote is seen by the West as a key democratic test for the small landlocked nation of 2.9 million, which has no history of transfers of power to an opposition through the ballot box.
But the campaign has already been marred by opposition claims that the government is preparing mass electoral fraud.
Ahead of the vote, the European Union delegation to Armenia and the US embassy said in a joint statement that they were "concerned by allegations of voter intimidation, attempts to buy votes, and the systemic use of administrative resources to aid certain competing parties."
There are also fears of violence after 10 people were killed in 2008 clashes between police and opposition supporters following the election of pro-Moscow President Serzh Sarkisian.
This time, the country aims to hold an exemplary vote to elect "a parliament trusted by society," the president told AFP in an interview in March.
He said his government "has made enormous efforts so that (Sunday's) milestone vote is flawless."
Analysts have said the vote is dominated by fierce competition between the ruling party and a coalition of opposition parties led by Gagik Tsarukian, a former arm wrestler who is one of the country's wealthiest businessmen.
A total of five parties and four electoral blocs are running in Sunday's vote, with 101 parliamentary seats up for grabs under a proportional representation system.
A party needs to clear a five-percent threshold to be represented in parliament, while an electoral bloc made up of several parties needs to garner at least seven percent of the vote.
Voting, which started at 0400 GMT and ends at 1600 GMT, will be monitored by international observers from the Organisation for Security and Cooperation in Europe.