The Quebec Police are holding a news conference this afternoon to address the accusations their officers attempted to incite violence at the Montebello Summit.
The news conference update is below.

By now many Canadians have seen the YouTube video and the CUPE pictures.
About 50 seconds in, after being asked to put down the rock, the undercover officer shoves David Coles. There certainly are other videos available to verify facts.

So today at a news conference, we have the police saying a protester gave their undercover cop the rock. (Initially it was not their cop)
No explanation of  the bottle in the back pocket noticed by a commenter at Stageleft.
There may be a reasonable explanation, it may not be a beer or wine cooler bottle, and the three undercover police may have been stone cold sober.  Later: Water bottle, pop bottle?  Plastic? Glass? I don’t have the tools to enlarge the photo. It’s in his back pocket for…?

Good to know those who protect and serve were just going around picking up the trash while they infiltrate, eh? A protester gave the uncover police officer a rock. That shouldn’t be difficult to prove. The officer hung on to it because… And when asked to drop it he didn’t because…

Plausible deniability: a political doctrine originally developed in the United States of America in the 1950s and applied to operations by the then newly formed Central Intelligence Agency The Central Intelligence Agency (CIA).

Plausible deniability involves the creation of power structures and chains of command loose and informal enough to be denied if necessary. The idea was that the CIA (and, later, other bodies) could be given controversial instructions by powerful figures — up to and including the president himself — but that the existence and true source of those instructions could be denied if necessary; if, for example, an operation went disastrously wrong and it was necessary for the administration to disclaim responsibility.

The doctrine had two major flaws. First, it was an open door to the abuse of authority; it required that the bodies in question could be said to have acted independently, which in the end was tantamount to giving them license to act independently. Second, it rarely worked when invoked; the denials made were rarely plausible and were generally seen through by both the media and the populace.

Political pressure has been put on Quebec Public Security Minister Jacques Dupuis. According to CJAD:

A spokeswoman for Public Security Minister Jacques Dupuis says the minister won’t comment on the actions of the officers because he doesn’t get involved in police operations.

But the official, who asked not to be named, said today that Quebec provincial police have been asked to provide an explanation.

CEP President David Coles says they are considering pressing criminal charges.
(About 50 seconds into the video one of the undercover officers shoves David Coles)

Dr. Dawg has a list of questions the media is not asking.

I’m posting the Montebello Security statement below the fold; with public anger, curiousity and more information coming out it doesn’t hurt to have a dated copy. 

It’s busy in Montreal at the moment, a block has been evacuated and part of the metro closed while they check cracks in the Bay department store, so information from the scheduled press conference may be slower in getting out..

 Update: CP

Insp. Marcel Savard defended the three agents today at a news conference in Montreal and and insisted they were not there to provoke demonstrators.

He also says one of the officers was given a rock by protesters but the officer had no intention of using it.

Federal Safety Minister Stockwell Day is now blaming the protesters:

VANCOUVER (CP) - Public Safety Minister Stockwell Day is defending the use of undercover police at a protest during this week’s NAFTA leaders’ summit and pointing fingers at demonstration organizers.

Day says video he’s seen of the incident at the Montebello, Que., meeting shows the undercover officers were exposed because they were not committing violence.

Let’s see the video Mr. Day. 

Update: The British Columbia man, Paul Manley, who shot the YouTube video (now at 190 thousand views) was at the Montebello Summit getting footage for a documentary. He was disturbed by what he saw in this incident. You can read his account here.

CBC
The Globe and Mail: Red faced Surete du Quebec promised they will review their practises.

Martin Courcy, an expert in conflict management who has advised several police forces in Quebec, including the SQ, says the mere fact an officer was holding a rock was an act of provocation.

“They could serve as models to others, and in that sense there’s provocation,” he said. Police infiltration is meant to defuse conflicts. “In this case, they didn’t defuse conflict, they provoked conflict.”

Unified Police Agencies Report Positively on Security at Montebello Summit
Papineauville, Tuesday, August 21, 2007 - The unified police agencies, which include the Royal Canadian Mounted Police (RCMP), Sûreté du Québec (SQ) and the Ontario Provincial Police (OPP), report positively on the security measures implemented to ensure public order and security during the North American Leaders’ Summit.