PORTLAND, Ore. (KOIN) – As helicopters continue to circle over Portland every night, residents have been left wondering: Why do I keep hearing helicopters outside my house?

U.S. Customs and Border Patrol confirmed to KOIN 6 News on Thursday that these helicopters have been deployed “in support of ICE operations.”

Since late September, these helicopters have frequented the area south of downtown Portland — near the U.S. Immigration and Customs Enforcement facility — and in the inner-Southeast Brooklyn neighborhood.

As a result, the City of Portland has noted an increase in noise complaints. But as the helicopters are not owned by the City of Portland, officials say the “significant noise” is out of their control.

“The aircraft appear to be federally operated, and the noise generated is not a development the City or our local partners can control,” the city said in a social media post Thursday.

KOIN 6 News asked CBP why these helicopters are in the city and how long they should be expected in the area.

“Due to the law enforcement sensitive nature of the operations, we cannot provide details of the number of assets deployed nor the duration of the mission,” a CBP spokesperson said.

There was one confirmed case in which an aircraft affiliated with CBP was involved in an arrest. On Saturday, Sept. 27, a laser pointer aimed at a helicopter led to the detainment of four undocumented immigrants, according to the FBI.

No other federal agencies have confirmed helicopters in the area.

KOIN 6 News reached out to the U.S. Department of Homeland Security for more information. This story will be updated when we hear back.

Stay with KOIN 6 News as this story develops.