(CNN) A 7-year-old girl is in critical condition at a New Delhi hospital after undergoing surgery for injuries she suffered while being raped with a water hose, officials said Wednesday.

Her mother was by her bedside after the girl underwent hours of surgery.

A 21-year-old has been arrested in connection with the rape, which occurred in the district of Shahdara in the northeastern part of the city, said Meghna Yadav, a deputy commissioner with the Delhi Police.

Yadav could not provide further details, she said. But Swati Maliwal, chairwoman of the Delhi Commission for Women, said the girl was in extreme pain after the attack.

Just met with 7 year old rape survivor who was brutally raped in Seemapuri yesterday by a 22 year old man. He took her to a park, inserted water pipe inside her private part & then raped her. Girl is v critical, has bled incessantly & was operated upon. Mom single parent, v poor! — Swati Maliwal (@SwatiJaiHind) September 18, 2018

"We are working out her rehabilitation plan," she told CNN. "It is very unfortunate that these rape cases are not ending in Delhi. Police resources continue to be extremely low in Delhi."