Authorities are warning CTA riders about a pair of strong-arm robberies earlier this month near the Cicero station on the West Side.In each incident, two suspects have approached victims and forcibly taken their phones while they were sitting on southbound Blue Line trains or exiting trains at the Cicero station, 720 S. Cicero Ave., according to a community alert from Chicago police.Both robberies happened on trains in the 700 block of South Cicero, the first about 6:40 p.m. on May 12 and the second about 9 p.m. on May 14, Be careful as you are out and about.