A cease-fire took effect on Wednesday evening following two days of heavy fighting that marked the largest outbreak of hostilities in nearly two years.
Armenian acting Vice Premier Armen Gevorkyan's apparent move to secure support from the Kremlin came as protesters in the capital Yerevan took to the streets for a fresh day of rallies.
According to Armenian law, lawmakers in the parliament, where Sarkisian's Republican Party have a majority, have a week to propose new candidates for PM and could hold a vote on May 2.
With protests against Armenian PM Serzh Sarkisian escalating, here is all you need to know about the country's troubled history
Armenia is facing a deepening political crisis, after talks between Prime Minister Serzh Sarkisian and protest leader Nikol Pashinyan failed.
Armenian police said protest leader Nikol Pashinyan was forcibly taken from a protest rally, dismissing reports of his arrest as riot police and demonstrators clashed in Yerevan.
Armenia's political turmoil deepened as Prime Minister Serzh Sarkisian stormed out of talks with opposition leader Nikol Pashinyan, who was later forcibly removed from a protest.