An assassination attempt on a presidential candidate in Armenia has thrown this month's election into doubt.

Paruyr Hayrikyan, an outsider in the 18 February presidential vote, was shot in the shoulder close to his home in the capital Yerevan on Thursday night. Doctors removed the bullet and said his life was not in danger.

The election, in which President Serzh Sarksyan is widely expected to secure a second five-year term, could be postponed for two weeks under the constitution if he is forced to pull out.

"It's a blow to the leadership of the country and our statehood," Prime Minister Tigran Sarksyan told reporters.

Stability is regarded as vital for the former Soviet republic of 3.2 million to woo investors and boost an economy devastated by a war with neighbouring Azerbaijan in the 1990s and then the 2008-09 global financial crisis.

Violent clashes broke out between opposition protesters and police in 2008, killing about 10 people.

Russia has a military base in Armenia, which is a member of a Moscow-dominated security alliance of ex-Soviet states.

Mr Hayrikyan, 63, is a Soviet-era dissident, who survived Soviet prison and internal exile as well as forced deportation from the Soviet Union to Ethiopia and the United States.

He is now the leader of a moderate opposition party, the National Self Determination Union and ran for president in 2003.