Nassau County police are investigating two separate armed robberies early Sunday -- both committed by three bicycle-riding suspects armed with a handgun and knives and wearing black masks and dark clothing.

One victim was injured. It was not immediately known whether the robberies were being investigated by authorities as linked cases involving the same suspects.

The first robbery occurred in Uniondale about 12:35 a.m. when a 25-year-old man walking on Laclede Avenue was approached by three males riding bicycles, armed with a handgun and a knife.

The suspects forced the victim onto his knees and went through his pockets, police said. They took cash, an iPhone and his backpack then fled on their bicycles westbound on Warwick Street.

Police said the second robbery occurred in Westbury about 1:20 a.m. when three subjects on bicycles, armed with a handgun and knives, approached two male victims, 17 and 20, who were walking near Old Country Road and Sylvester Street.

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Detectives said the suspects, speaking in Spanish, demanded the victims' property. One victim handed over his cellphone and wallet containing cash but police said the other victim refused and was struck on the head with the handgun, causing a small cut. The suspect then reached into the victim's pocket and removed his cellphone and wallet containing a credit card.

The three bicyclists fled west on Old Country Road and then went south on Grand Boulevard.

A further description of the suspects in that case is that they have thin builds and are in their 20s. Detectives said anyone with information could call Nassau Crime Stoppers at 800-244-8477.