PHOENIX -- Phoenix police are alerting the public about a suspicious man who has approached children as they were walking to school.Sgt. Tommy Thompson said there have been three incidents since Wednesday. One was near Southern and 23rd avenues and two were near 24th Street and Liberty Lane in Ahwatukee.Each of the incidents involved girls about 12 years old.Police said the suspect attempted to engage the children in conversation. In one of the cases, he asked the girls if they wanted to go to Mexico.A witness to one of the incidents said it appeared the man was trying to convince the girls to get in his truck. The suspect is described as an older Hispanic man with a balding or shaved head, mustache and sometimes wearing a ball cap. He was driving an older, full-sized red pickup truck.The girls were not harmed in any of the incidents.Thompson said at this time it does not appear that any crimes were committed in any of these incidents, but the activity is suspicious and officers would like to speak to the man.Anyone with information about the incidents or the man is asked to call police at 602-262-6151.