Two people including a minor have been arrested in Kingston, Ont., in connection with a national security investigation involving the FBI.

The RCMP, Kingston police and the FBI were all involved in the operations Thursday in what the RCMP described as an ongoing and evolving situation.

Sources tell CTV News that the operation was connected to a national security investigation. However, there is “no imminent threat.”

One of the two individuals arrested is a minor, according to sources. However, police have not identified either of the individuals arrested or provided information about possible charges.

Investigators were seen carrying armloads of sealed packages and bags from a house in downtown Kingston Thursday night. Photos shared on social media show heavily-armed officers, both in and out of uniform, outside a separate residence earlier in the day.

Public Safety Minister Ralph Goodale said in a statement Thursday that police officers carried out the operation “based on credible information, to ensure public safety.” Goodale did not disclose details of the arrests and said that any operational details will be made “at the appropriate time” by the RCMP.

The RCMP said it will address the operation Friday at a press conference in Kingston.

A plane seen flying over the city in recent days belonged to the RCMP and was connected to the case, sources said.

For weeks, Kingston residents have noticed unusual aircraft in the night sky. Some residents have complained of a buzzing sound starting in the evening and continuing late into the night.

When asked by CTV Toronto about the mysterious plane activity earlier this week, RCMP said that the agency has “multiple aircraft that support our mandate in Ontario and elsewhere in the country.”

“To maintain the integrity of our investigations and operations, the location of our aircraft is not disclosed,” the RCMP said in a statement.

The aircraft were not taking off or landing at Kingston’s local airport, according to the vice-president of the Kingston Flying Club.

Kingston police tweeted Thursday that there were no threats to the public and that “all actions are being taken to ensure public safety.”

Goodale noted that the official threat level for Canada remains at “medium,” where it has been since 2014.