An 11-year-old boy told police officers Wednesday he was grabbed by a teenager and then sexually assaulted. 

According to police, the incident happened on Magenta Avenue near White Plains Road.

They say the boy was grabbed from behind around 3:30 p.m., threatened with a knife and forced into a nearby park. The suspect then allegedly punched the victim, pulled down his pants and tried to force himself on the boy.

The child was able to escape. 

Another incident occurred Tuesday at the Bronx River underpass near Fordham Road. Investigators say a woman was tossed to the ground before her attacker grabbed her private parts over her clothes. 

That suspect took off after cars driving by started honking at him. Officers are calling that case an attempted rape.

Police do not believe the sexual assaults are connected in any way.