Almost four years since Sri Lanka's war ended, rage over the lack of rehabilitation for thousands of survivors of the bloody 25-year-long civil conflict has surfaced - not on the war-torn Indian Ocean island itself, but in neighbouring India.

India's Tamil Nadu state -- where the majority Tamil ethnic group have a close association with Tamils living across the Palk Straits in Sri Lanka - have long felt their brothers have been discriminated against by the Sinhalese-ruled government.

The war, pitting separatist Tamil Tigers against President Mahinda Rajapaksa's Sri Lankan Armed Forces, saw tens of thousands of mainly Tamil civilians in the north and east of the island killed or injured, and hundreds of thousands were displaced.

But even with the defeat of the Tigers and the end of the war in May 2009, disaffection over the treatment of Tamil survivors and their lack of rehabilitation remains a highly emotive issue amongst Indian Tamils, an issue which turned into violence this week.

Around 180 Sri Lankan pilgrims visiting Tamil Nadu were attacked by a mob of angry Indian Tamils on Monday, and were forced to hide inside a church until police could rescue them.