Thousands of Christians have taken shelter in makeshift government camps in Orissa state, where Hindu mobs went on the rampage last week after the murder of a Hindu leader, torching churches and damaging houses in a communally sensitive region.
Most of those killed were Christians.
Sporadic violence has continued, and police said on Thursday a mob of about 1,000 Hindu men and women had attacked a Christian relief camp, injuring two people. Local media reports said nearly 40 people had been hurt.
The Supreme Court asked the Indian government to deploy the additional federal police in Kandhamal, the worst-affected district in rural Orissa district.
"The counsel for the state of Orissa states that four more battalions of the CRPF are needed. The (federal government) may do so," the court order said.
The state government was also ordered to do more to protect Christians. Thousands of police have been deployed already in 12 of Orissa's 30 districts.
The order came after a petition was lodged by a Christian archbishop who had urged the court to stop a march planned by a radical Hindu leader in Kandhamal because of fears it could whip up communal passions.
Government counsels said the region was "very, very tense" and no religious march would be allowed there.
"The state government will prevent anything that would create a law and order problem," said Orissa state counsel K.K. Venugopal.
Last week's violence was largely a backlash against the murder of a Hindu leader who ran a local campaign against Christian conversion. Maoist rebels said they had killed him but Hindus blamed Christians.
Orissa is also beset by ethnic tensions.
Rivalry between local tribes and the Panas, an ethnic community, has flared up in a contest for government jobs and benefits reserved for underprivileged groups.
Hindus have backed the tribesmen against the largely Christian Panas to exploit that resentment.
The violence has drawn global condemnation, including from Pope Benedict, while Christian groups have appealed to the Indian government to protect community members in Orissa.
Collin Gonsalves, a lawyer for the Christian groups, told the court that a church and 50 Christian houses were burned even while the central home minister was on a tour of the affected areas on Wednesday.