Two San Bernardino County Sheriff’s Department deputies and two firefighters who work for different agencies within San Bernardino County have tested positive for the novel coronavirus, authorities said Sunday.

All four of the first responders were self-isolating and appeared to be doing well, according to sheriff’s and San Bernardino County Fire Department officials.

Both of the infected deputies were assigned to the department’s Detentions and Corrections Bureau, the department said in a written statement. It was not clear what specific facility they worked at.

“The deputies entered self-quarantine due to an onset of flu-like symptoms prior to receiving test results and have been off of work for a week,” according to the statement.

“We are currently investigating how they were infected. Although we do not know when and where the deputies were exposed to the virus, we continue to encourage all members to heed the warnings of health officials while on and off duty,” the statement said. “Out of respect for our deputies, no additional details regarding their identity or medical treatment will be released.”

Authorities also announced that two firefighters in San Bernardino County had contracted COVID-19.

One of the affected firefighters works for the San Bernardino County Fire Protection District, while the other works in the Montclair Fire Department, San Bernardino County Fire Department officials said.

“Both firefighters entered self-quarantine due to an onset of flu-like symptoms prior to receiving test results,” the agency said in a written statement. “Currently, the firefighters are feeling well and remain in isolation.”

San Bernardino County fire officials have been planning with regional partners for the possibility of first responders becoming exposed to or infected by the virus, the statement added. Contingencies and partnerships are in place to make sure fire, rescue and emergency medical services will not be interrupted.

The San Bernardino County Department of Public Health reported 111 infections and 3 deaths within the county due to COVID-19 as of Sunday.

The county saw its first cluster outbreak on Saturday, when officials announced that one resident had died and 12 others had tested positive for novel Coronavirus at the Cedar Mountain Post Acute nursing home in Yucapia. A resident at another nursing home in Mentone displayed symptoms of the virus but was awaiting test results.