Found summary of a nasty war between Tamil Hindus and Sinhalese Buddhists in Sri Lanka 1980s-2009:
The Tamil in Sri Lanka today are of various groups and castes, though they are predominantly Hindus. The so-called Ceylon Tamil, constituting approximately two-thirds of them, are concentrated in the northern part of the island. They are relatively well educated, and many of them hold clerical and professional positions. The so-called Indian Tamil of Sri Lanka were brought there by the British in the 19th and 20th centuries as workers on the tea estates, and they have been regarded as foreigners by the other ethnic groups. The Ceylon and Indian Tamil are organized under different caste systems and have little social intercourse with each other.
In the 1980s, growing tensions between the Ceylon Tamil and the Sinhalese Buddhist majority in Sri Lanka prompted Tamil militants to undertake a guerrilla war against the central government in hopes of creating a separate Tamil state for themselves in the north and northeast. The Tamil rebels’ organization, the Liberation Tigers of Tamil Eelam, continued their insurgency into the 21st century. A major government offensive in 2009 overran the final Tamil Tiger strongholds and destroyed the organization’s leadership. It was estimated that as many as 80,000 people were killed in the fighting.