Charred walls, collapsed tin roofs and smashed windows in a burned Kuki community church illustrate how deadly ethnic violence has led to brutal sectarian attacks in India's troubled Manipur state.

At least 120 people have been killed since May in armed clashes between the predominantly Hindu Meitei majority and the mainly Christian Kuki in the northeastern state.

The ruins of the Kuki church in Imphal are just one among the more than 220 churches and 17 Hindu temples destroyed in the months of vigilante violence, according to a report by India Today news magazine.

Across the street from the burned church, Baptist priest Zuan Kamang Damai led a service on Sunday with a congregation just a third of its usual size of about 800 after many of his Kuki parishioners fled.

"After this violence erupted, they moved to different places to save their lives," he said.

"They want to come back, they want to resettle, they want to live with my family," Damai said. "This is what they responded to me, and I comfort them. God is there."

Damai is himself a Naga, another major tribal group in the area who have largely been spared in the cycle of revenge attacks.

But many of his regular worshippers are staying away, fearful of the possibility of violence.

"We have to respect each religion -- regardless of Christians, regardless of Hindu, Muslim, whatever," the 55-year-old said.

While there was "conflict here and there", he said, "we have to avoid attacking the temples".

- Land, rights and power -

The cause of conflict is a complex mix of land, rights and power.

The Kuki oppose Meitei demands for reserved public job quotas and college admissions as a form of affirmative action, fearing that they might also be allowed to acquire land in areas currently reserved for tribal groups.

India's Interior Minister Amit Shah has promised a "thorough, in-depth and impartial investigation" into the violence and has said the government "stands shoulder-to-shoulder with the people of Manipur".

But the Human Rights Watch group says that state authorities, led by Shah's Hindu-nationalist Bharatiya Janata Party, have rolled out "politically motivated, divisive policies that promote Hindu majoritarianism".

Many say religious divisions are adding to the trouble.

While the majority Meitei people are largely Hindu, a small number are Christian and some say they too have been attacked.

B, a Meitei Christian who did not wish to be identified beyond an initial, described how he watched in horror as his church was burnt to the ground by a mob.

"The large-scale attack on churches across communities makes it evident that it has a religious angle to it," he said.

But others point out that while churches used by the Kuki community have been attacked, those of the Naga people have not.

Eva, a Christian with roots in both the Meitei and Naga communities who also asked for her real name not to be used, said the conflict is not just about land rights or government jobs.

"Meitei churches were vandalised and burnt," she said. "If it is just a Kuki and Meitei issue, then why were the Meitei churches attacked? The evidence is very clear cut."