A court in Armenia has opened a trial of the country's former president on charges stemming from a deadly police crackdown on a demonstration a decade ago.

Robert Kocharian, who has been jailed since December on charges of violating constitutional order for ordering the crackdown, contends the case is political revenge by Prime Minister Nikol Pashinian, who was a leader of the 2008 protest against election fraud.

Eight demonstrators and two police officers died in the clash.

The demonstration was protesting results of an election two weeks earlier that declared Serzh Sargsyan as Kocharian's replacement. Sargsyan, who was supported by Kocharian, served as president for the next 10 years before briefly serving as prime minister. Mass protests led by Pashinian drove Sargsyan out of office a year ago.