Armenian Prime Minister Nikol Pashinyan on Monday dismissed his foreign minister as several thousand demonstrators staged a new rally against a controversial peace deal with Azerbaijan.

Last week Pashinyan announced a Russian-brokered deal that ended six weeks of fierce clashes with Azerbaijan over Nagorno-Karabakh that left thousands dead and displaced tens of thousands more.

Armenia agreed to cede swathes of the disputed region to Baku, as well as other territories controlled by Armenian separatists since a devastating war in the 1990s.

The deal sparked fury in Armenia, where thousands of protesters took to the streets of the capital Yerevan, calling Pashinyan a "traitor" and demanding his resignation. Protesters also stormed and ransacked government buildings.

Pashinyan has ruled out his own resignation, but on Monday he announced that he had "decided to fire" Foreign Minister Zohrab Mnatsakanyan.

Several thousand opposition supporters gathered for a new rally in Yerevan on Monday, with many chanting "Nikol leave" and "Nikol the traitor".

Opposition politician Eduard Sharmazanov said that "even one more hour" of Pashinyan's rule was a threat to Armenia's security.

"We can only discuss with him one subject: his resignation," Sharmazanov said at the rally.

Pashinyan, whose wife and son were at the front during the conflict, has so far weathered the political storm despite the pressure.

Speaking to lawmakers in parliament on Monday, Pashinyan pointed to continued support from Armenia’s military and ethnic Armenian separatists in Karabakh.

He also reiterated that the peace accord was Armenia’s only option and that it ensured Nagorno-Karabakh’s survival.

Even though the disputed region lost swathes of territory, it will see its future guaranteed by some 2,000 Russian peacekeepers to be deployed for an initial period of five years.

Appeal for calm 

Earlier in the day Pashinyan appealed for calm as he spoke to supporters on social media.

"Today I clearly stated that violence or the provoking of violence [especially armed violence] cannot in any way be a means of action for the government,” Pashinyan said on Facebook.

He added that he expected the opposition to also declare that it did not back "any violent action”.

Authorities on Saturday said they thwarted a plot to assassinate the 45-year-old prime minister and arrested opposition leader Artur Vanetsyan, the former head of Armenia’s security services.

Vanetsyan, leader of the centre-right "Homeland” party, was released on Sunday after a court ruled that his detention lacked legal grounds.

A dozen opposition leaders were detained last week for inciting riots but were also released.

Nagorno-Karabakh declared independence from Azerbaijan nearly 30 years ago but it has not been recognised internationally, even by Armenia.

Clashes between Azerbaijan and Armenian separatists broke out in late September and persisted despite efforts by France, Russia and the United States to mediate ceasefires that collapsed as each side accused the other of violations.