Four people were injured in a 2-alarm apartment fire in the city’s Frankford section Friday afternoon, authorities said. Firefighters responded around 3:10 p.m. to the 5000 block of Akron Street and found flames on the second and third floors of the building. Police said two people were rescued and transported to Jefferson Frankford Hospital with minor injuries. The Fire Department said two other people also were transported to a hospital with nonlife-threatening injuries. At least 15 residents were displaced. The fire was declared under control at 3:40 p.m. The cause was under investigation.