Cops used an iPhone app to track down and arrest two youths who allegedly pointed a BB gun at five teens before robbing them in Brooklyn Saturday afternoon.

The teens told cops that they were in a playground at Bay 46th Street and Cropsey Avenue in Gravesend at about 12:30 p.m. when the two suspects brandished a gun and demanded their property. The pair snatched two cell phones from the teens before fleeing, cops said.

One of the victims’ mothers helped the officers to use the Find My iPhone app to track the stolen phones to Mermaid Avenue and West 19th Street. The system showed that the suspects were continuing to head west along Mermaid Avenue.

The cops broadcasted the suspects’ description, location and direction of travel over police radio.

Plainclothes officers responded and quickly realized that the suspected thieves were on a B74 bus, which they stopped near West 28th Street and Mermaid Avenue in Coney Island.

The cops boarded the crowded bus, spotted the suspects and brought them out onto the sidewalk, where they arrested them.

During a search, cops found them in possession of a Crossman Vigilante BB gun. They also recovered the two phones.

Rysheek Dixon, 20, and Timothy Wright, 15, were each charged with robbery, criminal possession of a disguised gun, criminal possession of a weapon, criminal possession of stolen property and menacing.