(CNN) -- Three children helping their mother operate a fruit stand were killed Friday when a stolen SUV plowed into a small crowd on a Philadelphia street corner. A 10-year-old boy was pronounced dead on the scene, and his 7-year-old brother and 15-year-old sister were later pronounced dead at the hospital, said Lt. John Stanford of the Philadelphia Police Department. The children's 34-year-old mother remained in critical condition Saturday morning, he said. None of the victims' names has been released. Philadelphia police said two men carjacked a real estate agent who was showing a house and pushed her into the backseat of her Toyota SUV. The men drove around Philadelphia at high speeds while holding the woman at gunpoint, police said. At some point the SUV had a flat tire, but the men kept driving, police said. The vehicle rounded a corner at Germantown and Allegheny avenues and ran into a small crowd on the corner, including the fruit stand where the family was raising money for their church, police said. "I saw these kids on the ground, the woman on the ground crying, their clothes ripped off them," Jesse Bridges of Eagle's Wings Evangelical Church told CNN affiliate KYW. Another woman helping at the fruit stand and the SUV owner also were hospitalized, police said. The SUV wrecked in a wooded area and the two men ran away, police said. A reward of $110,000 is offered for information leading to their arrest. The father of the 7-year-old boy urged the suspects to surrender to authorities. "Taking innocent peoples' lives. That was my son," he told KYW. "You took him away from me. Turn yourself in." "They were sweet," Ursula Jackson of North Philadelphia said of the three children. "They were beautiful, they were beautiful little kids."