Thousands of people are blocking a major road in downtown Bucharest to protest plans to build what would be Europe's biggest gold mine.
Protesters marched past government headquarters on Sunday yelling, "Your treason is measured in gold!"
Canada's Gabriel Resources has been trying to gain permits to go ahead with the planned mine in northwest Romania for 14 years. Parliament is due to vote in the coming weeks on whether to back the project.
Opponents of the mine criticize plans to use cyanide in the extraction process, while others say Romania would earn too little from the open cast mine, for which four mountains would be razed.
But supporters argue that the project would create jobs for unemployed miners and provide vital foreign investment to a deprived area.