Tens of thousands of supporters of Armenia's protest leader, Nikol Pashinyan, have responded to his call for civil disobedience, blocking key roads and government buildings.
He has led weeks of anti-government protests that forced Serzh Sargsyan to resign after 10 years in power.
Mr Pashinyan called for a general strike after ruling party MPs refused to back him as interim prime minister.
Protests broke out across the capital Yerevan and other main cities.
Cars and lorries blocked intersections in the capital, while demonstrators stopped traffic on the route to the main airport. Tourists had to abandon vehicles and carry their luggage. Metro stations in Yerevan were closed as part of the campaign of disobedience.
Teachers and school students were among those taking part in the protests in the landlocked former Soviet state of 2.9 million people, a close ally of Russia. The southern Caucasus country shares borders with Turkey, Georgia, Iran and Azerbaijan.
Mr Sargsyan left the presidency last month after 10 years in power and was then elected prime minister by a parliament controlled by his Republican party. Under a 2015 referendum marred by irregularities, Armenia shifted powers from the president to parliament.
Mr Sargsyan's move was seen by critics as a way of clinging to office.
Demonstrators poured on to the streets of Yerevan after Mr Pashinyan addressed crowds on Tuesday night in Republic Square, close to parliament.
He told the BBC
on Wednesday that protesters were fighting for their rights and dignity. "I want to be clear, it isn't a fight for Nikol Pashinyan becoming prime minister, it's a fight for human rights, for democracy, for rule of law and that is why our people aren't tired and won't be tired."
The acting head of government, Karen Karapetyan, has called for talks to end the crisis.
"A prime minister should only be elected in parliament according to the constitution," he said.