Armenian protesters on Tuesday blocked streets in the capital Yerevan, launching a "civil disobedience" campaign to force Prime Minister Nikol Pashinyan to quit over a controversial peace agreement with Azerbaijan.

Shouting "Armenia without Nikol" and "Traitor", opposition supporters blocked traffic across the capital and paralysed the city's subway. Police detained dozens of demonstrators.

In a fresh blow to the embattled premier, the influential head of Armenia's Apostolic Church, Catholicos Garegin, on Tuesday called for Pashinyan's resignation "to avoid tragic developments" and pointed to "mounting tensions in society".

Last week, 17 opposition parties said Pashinyan had until Monday to step down and proposed that former prime minister Vazgen Manukyan take over his duties.

Pashinyan, 45, has been under huge pressure since agreeing on November 9 to a Moscow-brokered deal with Azerbaijan that ended six weeks of fierce fighting over the disputed region of Nagorno-Karabakh.

Several thousand people have died in the conflict.

Under the agreement, Yerevan ceded to Baku parts of the disputed enclave and seven adjacent districts of Azerbaijan controlled by Armenian separatists since the 1990s.

The decision sparked fury in Armenia, where demonstrators stormed and ransacked government buildings and briefly took control of Pashinyan's residence while he went into hiding.

Some 10,000 demonstrators rallied in central Yerevan on Saturday in the protest movement’s biggest protest so far.

Pashinyan, whose wife and son were at the front during the conflict, has said he has no plans to quit and the peace deal was Armenia’s only option, ensuring Karabakh’s survival.

Even though the ethnic Armenian enclave lost swathes of territory, it will see its future guaranteed by nearly 2,000 Russian peacekeepers deployed for a renewable five-year mandate.

The Armenian authorities last month said they had thwarted a plot to assassinate the prime minister.