The letter comes after the US Commission on International Religious Freedom (USCIRF) in August put India under its Watch List for the "country's failure to protect the rights of religious minorities".
The letter hasn't gone down well with Hindu organisations. "Who're they to interfere in Orissa's internal problems?"
Bajrang Dal leader Subash Chouhan asked, "How can anyone say that Christians are the victims of violence at a time when bombs and firearms are being seized from Christian rehabilitation camp?"