Police said the peadophile is a 25 year-old Indian man. He was arrested at the high-security compound on Sunday a day after the alleged incident at the living quarters for local housekeeping staff.
Police officer Yogesh Kumar said preliminary medical tests confirmed the girl had been raped. The man was charged under child rape laws that carry the death penalty.
The sprawling diplomatic compound is one of the most secure in Delhi, with multiple layers of manned and electronic security.
A US Embassy spokesperson in New Delhi said Friday that it was “deeply disturbed” by the allegations and it took “prompt action” including reporting the incident to the police and helping arrange medical assistance.
“We are cooperating with the Indian-led investigation. We extend our sympathy and full support to the child and her family,” the spokesperson said in a statement.
India is struggling to combat a growing number of sexual assault cases in the country.
Violence against women in the South Asian nation has been under the international spotlight following the brutal gang-rape and murder of a Delhi student on a bus in 2012.
Almost 34,000 rapes were reported in 2018, according to official data, with activists claiming the figure is just the tip of the iceberg.