Three juveniles were stabbed in separate incidents in Brooklyn and Queens Thursday afternoon.

A 12-year-old boy was in critical condition after being stabbed in the chest in Brooklyn, the NYPD said. 

It happened just before 3 p.m. Thursday at a playground at Thomas Boyland Street and Dumont Avenue in Brownsville, Brooklyn. 

The boy was rushed to the hospital and is in critical but stable condition. 

Two other juveniles are in custody, police said. 

It wasn't immediately clear what led up to the stabbing. 

In a separate incident in Queens, two 13-year-olds were stabbed at Seneca Avenue and Palmetto Street in Ridgewood. 

It happened at around 4:50 p.m. Responding officers found a 13-year-old stabbed in the chest and a 15-year-old stabbed in the back. 

Both were rushed to a local hospital in stable condition. 

So far, there have been no arrests in that incident.