CHICAGO (CBS) — Armed robbers have been knocking cyclists down on or near The 606 trail to steal their bikes, and Chicago police were warning people who use the popular trail to be on the lookout.

Police said cyclists have been targeted in at least three robberies on the trail this month, according to a community alert.

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Most recently, two men knocked down a cyclist at 1850 N. Ridgeway Ave., just north of the westernmost entrance to The 606, around 4:30 a.m. Sunday. Police said one of the robbers was armed with a black handgun.

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The attacks have not happened only when it’s dark. On Saturday, around 5:30 p.m., another victim was robbed on the trail at Spaulding Avenue.

The first attack this month was reported around 1:15 a.m. on July 2, on the trail at St. Louis Avenue.

The 606, also known as Bloomingdale Trail, is a former elevated railway that has been turned into a running and cycling trail and park stretching through Bucktown, Wicker Park, Logan Square, and Humboldt Park.

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Police were warning trail users to be vigilant, and be aware of their surroundings.