YEREVAN, Armenia — Armenians began voting on Sunday in an early parliamentary election as Acting Prime Minister Nikol Pashinyan sought a stronger mandate, having been elected by lawmakers in May after a peaceful revolution this year.

Mr. Pashinyan came to power after weeks of mass protests in April against corruption and cronyism in the former Soviet republic. A former newspaper editor who was jailed for fomenting unrest in 2008, Mr. Pashinyan represents a drastic break from the cadre of rulers who have run Armenia since the late 1990s.

He stepped down in October so that Parliament could be dissolved in readiness for the early election. Former high-ranking officials were dismissed, and some were arrested following the power change. On Friday, a court of appeal ordered the detention of former President Robert Kocharyan on charges of attempting to overthrow the constitutional order.

He was first arrested in July but freed the following month, and the case was sent to the appeals court. Mr. Kocharyan was Armenia’s second president, serving from 1998 to 2008.