Four off-duty D.C. plainclothes police officers chased, then shot and seriously wounded a young man from El Salvador who allegedly threatened them with a gun Wednesday night near 17th and O streets NW.

The pistol, which police say Juan Jorge Guzman, 20, pointed at them three times in the course of their pursuit, turned out to be a toy.

According to police department spokesman Joseph Gentile, the four plainclothes officers, whose shift in the Third District had ended at 11 p.m. Wednesday, were standing near one of their cars in an O Street parking lot chatting, when Guzman approached them brandishing a gun.

Gentile said they immediately identified themselves as policemen and ordered Guzman to drop his weapon. He turned and ran, with all four officers pursuing him on foot, Gentile said.

Guzman finally took cover behind a car in front of 1401 17th St. NW, according to Gentile.When he pointed the gun at them again, Officers Glenn Gilmore and Rick Vavrick opened fire on Guzman, wounding him twice in the hip, Gentile said.

Guzman, interviewed yesterday in the lockup ward at D.C. General Hospital where he is being held on charges of assaulting a police officer, said that he never heard the police identify themselves.

"I thought they were thieves," because of their ordinary clothes, GUZMAN said in Spanish. He has been in this country five months and speaks only rudimentary English, he said.

Guzman, who lives at 1009 11th St. NW and works at a waterfront restaurant, said he bought the toy gun at a drugstore a few days ago to send to a nephew in El Salvador. He said it was in his pants pocket when the four men ordered him to put his hand up and he started running.

He denied the claim by police that he had a gun in his hand or was brandishing it when he first encountered the officers.

Guzman was listed in satisfactory condition at the hospital.