Two men, identified as 26-year-old Nicholas Ruiz and 26-year-old Larry Carino, both Los Angeles residents, were arrested in connection with the incident.
According to sheriff's spokeswoman Cindy Bachman, Deputy Robert Jahn was conscious after being airlifted to Colton's Arrowhead Regional Medical Center, where he underwent surgery.
News video from outside the hospital showed the deputy sitting partially upright on a gurney as he was wheeled into the emergency room by colleagues and medical personnel.
DEVELOPING: San Bernardino Co. Sheriffs deputies are working to apprehend suspect who shot deputy in Adelanto; deputy is alert at Arrowhead Regional Medical Ctr. | LIVE UPDATE on @ABC7 6am. https://t.co/a8eFAqjJ8p #abc7eyewitness pic.twitter.com/INfCvzMsGS— Marc Cota-Robles (@abc7marccr) October 18, 2018
Deputies were conducting an unrelated traffic stop about 1 a.m. in the 18000 block of Bellflower Street when they heard gunfire erupt nearby, sheriff's Sgt. Marc Bracco said. The shootout that left Jahn with multiple wounds happened after they responded to an apartment building, the sergeant said.
A massive law enforcement presence, including a SWAT team, descended on the scene.
Shortly before 7 a.m., authorities announced that two men and a woman were detained, adding that a search of the building for possible additional suspects was ongoing. The woman was said to be a witness.
Sheriff John McMahon later held a press conference outside the hospital, where he identified Jahn, a five-year veteran of the department, who was struck below the bulletproof vest he was wearing.
"As you may be aware, this is the third event in the last 14 days where our deputy sheriffs were fired upon by suspects in this county," McMahon said. "It's important to remember that we have a great deal of community support in the county of San Bernardino, but there are some dangerous people on the street."
Jahn, a married father of four teenage daughters, was joined at the medical center by his family, the sheriff said.
"According to the doctors, went through the abdomen and struck several organs, and they treated and fixed those the best of their ability," McMahon said.
A handgun was recovered at the crime scene and no other suspects were being sought, McMahon said. The motive for the shooting is under investigation.
Thank you for the support, thoughts and prayers for Deputy Robert Jahn as he recovers from this morning’s deputy involved shooting. Robert is in critical but stable condition. pic.twitter.com/CyTMdh7uIy— John McMahon (@sheriffmcmahon) October 18, 2018