Merced police responded to a report of sexual assault Sunday night at an apartment in the 200 block of Seneca Street.
The incident was reported just after 11 p.m., according to Sgt. Alan Ward.
The victim, who is in her early 20s, said she was walking to her apartment with laundry when she heard someone run up from behind.
She turned toward the sound of the footsteps and dropped her laundry, fearing she was going to be attacked.
The woman turned and saw her attacker -- a man naked from the waist down. The attacker grabbed the woman around the waist and sexually assaulted her, police said.
The victim said she was able to fight off the attacker and he ran from the scene. The assailant was described as a Latino man in his early to mid-30s, wearing a long sleeve black shirt.
Police are asking witnesses or anyone with information about the assault to call Sgt. Scott Skinner at (209) 385-4702 or the department's automated tipline at (209) 385-4725. Tips are kept confidential and you can remain anonymous.