Pro-government parties in Armenia have won the largest share of the vote in the country's parliamentary elections, according to preliminary results.
Mr Sarksyan's Republican Party was expected to win the election
The ruling Republican Party of Prime Minister Serzh Sarksyan won almost 33% of the vote, officials said.
European observers said the vote largely met international standards, but that some more work was needed.
Opposition groups said Saturday's vote was falsified and have called for mass demonstrations in the capital, Yerevan.
Armenian officials have insisted the election was calm, positive and lawful.
This was Armenia's fourth election since it gained independence in 1991, but the last, in 2003, was judged not to have met democratic standards.
More than $200m of US development aid and the prospect of closer links with the European Union was at risk if the polls were condemned as unfair.
Preliminary results released on Sunday by electoral authorities showed the Republican Party had won more than 32.8% of the vote.
Prosperous Armenia, a comparatively new political party led by former world arm wrestling champion Gagik Tsarukian, won 14.7%.
Only two opposition parties, the Rule of Law Party and Heritage, passed the threshold needed to get seats in parliament.
Turnout was almost 60%, officials said earlier in the day.
The BBC's Matthew Collin, in Yerevan, said the results were a resounding victory for pro-government forces.
A spokesman for the Law-Governed Country Party, Tigran Mkrtchyan, said the results were "grossly falsified".
But a report observers from the Organisation for Security and Co-operation in Europe praised the conduct of the vote.
"The election campaign was dynamic with extensive media coverage. Election day was calm, with no major incidents reported, but a few cases of fraud schemes were observed," the OSCE said.
"These Armenian elections were an improvement over previous elections and were conducted largely in accordance with international standards," the report added.
The chairman of Armenia's electoral commission also denied allegations of widespread fraud.
But Mr Mkrtchyan accused pro-government parties of handing out bribes at polling stations, and said the opposition would organise mass demonstrations in Yerevan on Sunday to attempt to overturn the results.
Large protests after the country's last disputed election were broken up by police and the authorities have already warned they will not tolerate unrest.