CHICAGO (CBS) — Police are going through extensive extra training for the NATO/G8 summits, as two groups of demonstrators have now announced plans to march down Michigan Avenue in the midday hours.

As WBBM Newsradio’s Dave Marsett reports, the Chicago Tribune says as it is, more than 2,000 officers have received five days’ training for the summits, compared with a mere eight hours’ training for the last big event involving demonstrators in Chicago.

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LISTEN: WBBM Newsradio’s Dave Marsett reports

Police Bureau of Organization Development Chief Brian Murphy told the Tribune that another 6,000 officers have received two days’ training, in case they are called in to respond during the summits in May.

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Some officers were sent for training at a U.S. Department of Homeland Security facility in Alabama, so they could be trained as instructors to teach other officers in a three-day course on crowd control, the Tribune reported. The Police Department has added two more days of training, the newspaper reported.

In total, sources tell the Tribune that about 8,400 of the approximately 12,000 sworn officers have been through some kind of crowd control training for the summits – although the Police Department will not provide any official figures.

There have been estimates that between 2,000 and 10,000 demonstrators will show up at the summits between May 19 and 21.

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A notice posted last month by the Vancouver-based Adbusters Culturejammers called on 50,000 protesters to come to the city durig the summit.