Two teenage students were injured by gunfire inside a Philadelphia high school Friday and police were looking for the suspected shooter who fled the scene, a police official said, according to dpa. It was the second school shooting in the United States this week and the third since December 13. The shooting occurred right before 3:30 pm (1930 GMT) at Delaware Valley Charter High School, a police officer in the East Coast city said in broadcast remarks. The victims, one male and one female, were each 15 years old and were in stable condition with non-life-threatening injuries. The officer said he believed each had suffered one wound from a hand gun. A SWAT team put the school on lockdown and cleared it, releasing students one by one. Police declared that it was no longer an active shooter situation. With the increasing number of school shootings in the US, police now take a much more aggressive role in entering schools as quickly as possible when called. Earlier this week in the south-western state of New Mexico, a 12-year-old student shot and seriously injured two fellow students at a middle school in the town of Roswell. The December 13 shooting occurred in a suburb of Denver and left a 17-year-old high school student dead. Another student received minor injuries before the accused attacker shot and killed himself. According to stoptheshootings.org, an online school shooting database, there have been 387 school shootings in the US since 1992. One of the worst occurred in December 2012 when 20 children and six educators were shot dead at Sandy Hook elementary school in Newtown, Connecticut. Efforts to bring about stricter gun controls, led most recently by US President Barack Obama, have come up against strong resistance by the gun lobby which insists that private ownership of military-style large clip rifles of the sort used by the Newtown shooter is protected by the US constitution.