Police have released surveillance pictures of two men they say are responsible for multiple knifepoint robberies in Brooklyn. 

They say the men are responsible for robbing three women inside three stores in Brooklyn since April 8. Police say the men work as a pair; one of them enters the stores with a knife and demands money, while the other stands guard outside. 

They say the men robbed the Area Play store on Smith Street, stealing $300 and a woman's cellphone and credit cards on April 8.

The men also robbed the Pink Olive on 5th Avenue on April 28, stealing $841 and a woman's credit cards and cellphone. 

Also, police say the men robbed the Tiny Brooklyn Clothing store on May 3, and got away with $245 and a woman's cellphone and credit cards. 

Police say up until recently they did not know who the two men were, but when they used one of the victim's credit cards on a livery cab, police were able to obtain surveillance images from the cab ride. 

Police say anyone with information is asked to call the NYPD's Crime Stoppers hotline at 1-800-577-TIPS.