A CTA Blue Line train stops downtown. View Full Caption DNAinfo/Justin Breen

CHICAGO — The Chicago Police Department has warned Blue Line riders to remain vigilant after two recent robberies in The Loop.

In both incidents, the robbers used physical force to take iPhones and/or iPads.

The first incident occurred near the Monroe Blue Line about 6 a.m. July 16.

The two robbers were described as black males, approximately 19 years of age with dreadlocks and medium complexions.

In the second incident, which occurred near the Clark/Lake Station at 2 p.m. July 18, the robbers were described as two black males between the ages of 19-22.

One robber was described as being about 6 feet tall and weighing 160 pounds with curly hair and medium complexion.

The second robber was said to be 5 feet, 7 inches tall and weighing 160 pounds.

Anyone with information is asked to call the police at 312-747-8380.