BROOMFIELD, Colo. (CBS4) — You may be seeing — and hearing — Army helicopters in the skies over the metro area for the next few weeks.

FILE PHOTO: US Army Black Hawk helicopter (credit: JOSEPH EID/AFP/Getty Images)

“The United States Army is performing flight operations near Arvada for what could be the next few weeks. There will be an increased presence of helicopters near Rocky Mountain Airport,” the Arvada Police Department tweeted Wednesday.

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Rocky Mountain Metropolitan Airport (credit: CBS)

One Twitter user asked why the community wasn’t informed earlier.

“We weren’t informed so we’re just as surprised as you are!” the Westminster Police Department replied.

“The flight tower at Rocky Mtn airport said the Army is performing flight operations and refueling at the airport said it may be going on for a couple of weeks,” Westminster police tweeted. “They didn’t tell us what ‘flight operations’ were but they are not actively looking for anyone.”

Several people on Twitter complained the helicopters seemed to be flying very close to homes.

“Have four large low-flying military helicopters shaking houses around Denver,” one person tweeted.

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“They sound so close when they are flying over our area,” one person commented.

“At tree top level – not cool! Shaking pictures of the wall,” another wrote.

People reported seeing and hearing them in lower downtown Denver and suburbs including Westminster.

“Just had a 2nd round of low-level flybys of choppers in Westminster,” Adam Zolyak wrote.

“They literally shook the house. *All* my neighbors were out to see what was flying over. For a bunch of typically uninterested types, and for a below-freezing night, that’s saying a lot,” Bendan Murphy wrote.

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Arvada police said there is no cause for concern and no need to report the activity.