Two people were taken to hospital after being shot by US federal agents in Portland, Oregon, police said on Friday. 

The incident has added to growing tension in the area, with officers urging residents to stay calm while investigators work to find out what happened following a separate shooting a day earlier in Minneapolis.

“Two people are in the hospital following a shooting involving federal agents,” Portland police said in a statement.

“We understand the heightened emotion and tension many are feeling in the wake of the shooting in Minneapolis, but I am asking the community to remain calm as we work to learn more,” police chief Bob Day said.

Police said they were not involved in Thursday’s shooting.

The FBI said it was probing the shooting in which US Customs and Border Protection agents were involved.

“Their conditions are unknown. Officers have determined the two people were injured in the shooting involving federal agents,” Portland police said in their statement.

Portland City Council president Elana Pirtle-Guiney was cited by an ABC News affiliate as saying that, as far as she knew, they were still alive.

“FBI Portland is investigating an agent-involved shooting that happened at approximately 2:15 pm near the 10000 block of Main St. in Portland,” FBI Portland said on social media.

Further details on the circumstances of the shooting in Portland were not immediately clear.

On Wednesday, a US Immigration agent’s fatal shooting of a 37-year-old mother of three in Minneapolis drew condemnation from local officials and sparked widespread protests in Minnesota and beyond.