UPDATED: 8/30/2012 6:15 a.m.

CHICAGO (CBS) — A Chicago Police officer was shot and wounded Wednesday night in the Morgan Park neighborhood.

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The officer and one other person, a 15-year-old boy, were shot near 111th and Loomis streets.

The 35-year-old officer was shot in the knee and taken to Advocate Christ Medical Center in Oak Lawn, according to the Chicago Fire Department. Sources said his injuries were not life-threatening.

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The other person who was shot, a teenager, was also taken to Christ, and was in serious condition, according to the Chicago Fire Department.

About 8 p.m., plain clothes officers stopped three teenage boys for “suspicious activity,” police said. But the 15-year-old boy fired at the officers and “engaged in a gun battle,” said Police Supt. Garry McCarthy.

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The officer is “very fortunate,” “in pain” and “annoyed,” McCarthy said

Two residents said the officer fired his gun first, according to the Sun-Times Media Wire service.

Phillip Jackson lives on the 111 block of South Loomis, a shorrt distance from the shootings. He says he knew right away that bullets were being fired.

“I knew it was gunfire,” Jackson told WBBM Newsradio. “I served in the Marine Corps, so I know the difference between firecrackers and gunfire. So when I heard the gunfire, I came out of the house. By the time I got to my front porch, I heard the sirens.”

Officers recovered a weapon on the scene, said McCarthy, who added several shots were fired.

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After the shooting, police swarmed over the Morgan Park neighborhood and detained two other boys, ages 15 and 16.