Protesters disrupted a mining conference at the Four Seasons Hotel in Vancouver Thursday afternoon by throwing a bag filled with feces into the room, police say.

Half a dozen people made their way up to the third floor, pulled the alarm and threw a bag containing "an extremely smelly substance" into the meeting room, according to a police statement. Investigators later determined the substance was feces mixed with a liquid.

"It was definitely excrement of some kind," Byron Goerz, who was at a conference of the B.C. Government and Service Employees' Union next door, told reporters. "It was pretty bad, it was really bad."

The protesters left shortly after disrupting the meeting and the affected floor was locked down. No arrests have been made.