BROOKLYN - Cops are asking for help tracking down four men wanted for two separate subway robberies in Bed-Stuy.

According to authorities, two men first robbed a 19-year-old at gunpoint last Friday on the platform of the Franklin Avenue station. The victim's chain was stolen, but he was not hurt.

Police say another two men roughed up a second victim and stole his iPhone at the Utica Avenue train station.

Anyone with information on either robbery is asked to call Crime Stoppers at 1-800-577-TIPS.