Armenia and Azerbaijan agreed on a deal with Russia to end weeks of fierce clashes over Nagorno-Karabakh on Tuesday, after a string of Azerbaijani victories in its fight to retake the disputed region.

The announcement of a full ceasefire from 1:00am on Tuesday (2100 GMT) sparked outrage in Armenia, with angry protesters storming the government headquarters in Yerevan where they ransacked offices and broke windows.

Crowds also seized control of parliament, calling from inside the chamber for the resignation of Prime Minister Nikol Pashinyan after he announced the “painful” deal to the end the fighting.

“I have signed a statement with the presidents of Russia and Azerbaijan on the termination of the Karabakh war,” Pashinyan said, calling the move “unspeakably painful for me personally and for our people”.

“I have taken this decision as a result of an in-depth analysis of the military situation,” he added.

Azerbaijan’s President Ilham Aliyev said Pashinyan had been left with no choice but to sign the “historic agreement”.

“An iron hand forced him to sign this document,” Aliyev said in televised remarks. “This is essentially a capitulation.”

Russian President Vladimir Putin confirmed that both Armenia and Azerbaijan had agreed to “a total ceasefire” that would create the conditions for a long-term settlement of the conflict.

He said the two sides would hold on to areas under their control and that Russian peacekeepers would be deployed along frontlines and to secure a corridor connecting Nagorno-Karabakh with Armenian territory.

Russian news agencies quoted the defence ministry as saying 1,960 peacekeepers would be deployed with 90 armoured vehicles.

Aliyev said Armenia had agreed to a timetable to withdraw its forces from large parts of the region and that Azerbaijan’s ally Turkey would be involved in implementing the ceasefire.

The deal would end six weeks of fierce clashes over Nagorno-Karabakh, an ethnic Armenian region of Azerbaijan that broke away from Baku’s control during a bitter war in the 1990s.