India's prime minister has pledged to stem fighting between religious groups in the wake of Christian-Hindu violence that has left at least four people dead and hundreds of Christians seeking shelter in relief camps. The violence, which occurred last week in a remote corner of Orissa state, broke out on Christmas Eve when long-standing tensions between the Hindu majority and the small Christian community erupted over conversions to Christianity. Prime Minister Manmohan Singh, in a letter dated Dec. 30 sent to the widow of a Christian missionary killed by Hindu hardliners in 1999, promised to uphold India's secular constitution and "safeguard the fundamental rights and liberties of all sections of our society." "We are taking all steps to ensure the restoration of normalcy and to bring about harmony and peace in the affected areas," Singh wrote to Gladys Staines of Australia, the widow of missionary Graham Staines, who was killed in 1999 along with his two sons. "Please be assured that we will not tolerate any efforts aimed at disturbing the communal harmony or secular fabric of our country."