Opposition leaders brought jars full of raw sewage into a council chamber and then smashed them on the floor during a scuffle.
Opposition party Erktsir Tsyrani was making an emphatic point about the conditions residents were living in because of broken sewage pipes in the Armenian capital city of Yerevan.
Party leader Mariam Khachatryan and her colleagues walked into a meeting of the Council of Elders, which governs the city, carrying two containers of raw sewage.
She walked straight towards the mayor, Taron Margaryan, 39, who was chairing the meeting, clutching the jars while wearing surgical gloves and a face-mask.
But rival council members stepped into her path and a scuffle broke out during which first one, and then the other, jar fell onto the floor and smashed open.
The horrific smell forced the Council of Elders to postpone the meeting and evacuate the chamber. One member, veteran jazz composer Martin Vardazaryan, 79, needed hospital treatment.
Ms Khachatryan later revealed that she had been making a point about the unbearable smells being suffered by residents of the Nubarashen district of the city where officials had done nothing to fix a broken sewer.
The incident was filmed by journalists covering the meeting and the footage is proving popular online after being posted on video-sharing platforms.
Netizen ‘Maniakalniy Bred’ said: "They should have put it next to a fan".
Yerevan is one of the world’s oldest continuously inhabited cities, dating back to the founding of the fortress of Erebuni in 782 BC by king Argishti I.