The appropriate concept for the given statement is the LTTE (Liberation Tigers of Tamil Eelam). The LTTE was a separatist terrorist organization that operated in Sri Lanka from the early 1980s until its defeat in 2009. The group fought for an independent Tamil state, Tamil Eelam, in the northern and eastern regions of Sri Lanka.
The LTTE was led by Velupillai Prabhakaran and was responsible for numerous violent acts, including bombings, assassinations, and suicide attacks. One of the most notable attacks was the assassination of former Indian Prime Minister Rajiv Gandhi in 1991. The organization was known for its innovative use of suicide bombings, which made it one of the most feared and notorious terrorist groups of its time.
The LTTE was designated a terrorist organization by many countries, including India, the United States, and Canada, due to its use of violence and its separatist agenda. Despite its defeat in 2009 by the Sri Lankan government, the legacy of the LTTE continues to affect Sri Lanka and the broader region.