PHILADELPHIA -- Two students were wounded Wednesday in a shooting at a convenience store across the street from their high school, police said.

The victims, an 18-year-old woman and a 17-year-old boy, ran into Olney High School for help after being shot, police spokeswoman Beth Skala said.

Police detained at least one woman and questioned others, but did not immediately file any charges, detective Steven Grace said Wednesday afternoon. Officers climbed rooftops in the area to look for weapons but did not find any, a police spokesman said.

The young woman was in stable condition with a gunshot wound in the buttocks and the boy was released after treatment for a thigh wound, Philadelphia School District spokesman Joe Lyons said.

The city and its schools have faced persistent gun violence. Last week, two men were sentenced to life in prison for a gunfight outside an elementary school that killed a 10-year-old in February 2004.

However, Lyons said serious incidents at Olney High -- including assault, drug and weapons offenses -- have fallen 30 percent this year, from 208 reports to 144. The school has two separate student bodies of about 1,000 youngsters each.

Anyone entering a district high school must pass through a metal detector. The Philadelphia School District has just under 200,000 students.