One more little indication that these guys don't play around: every Tamil Tiger carries a cyanide capsule into battle. You're supposed to take it if you're captured -- and these guys actually do. There's only two armies I know of in the world where they actually use cyanide capsules: the Tamil Tigers and the North Korean People's Army. That's some serious company to be keeping.
Up against the Tigers is the Sri Lankan army. It's nothing special. On paper it's bigger: 150,000 troops, 70 MBTs, 500 APCs (a weird mix of M113s and BMPs), a decent-size navy and small air force. The tanks are mostly T-55s, which means the army doesn't even have a technological edge in tank battles against the Tigers.
The air force uses a sad Argentine CI ground-attack plane called the Pucara. The Pucara had a pretty sorry record in the Falklands War: every single one the Argentines had was either shot down, destroyed on the ground, or captured. In exchange, the entire fleet of Pucara shot down...one British helicopter. I bet those Tamils are just quakin' in their boots every time they hear those heavy-duty Argentine engines getting closer.
The mainline fighter is the Kfir. This is a weird hybrid Israeli design. Basically, the Israelis stole everything they could from Mirage, then stole the rest from US designers, and called the result a new Israeli-produced fighter, the Kfir ("Lion" in Hebrew). It's the sort of big steal the Israelis seem to get away with time after time, and it's made them a lot of money in sales to third-world air forces.
But the air force can't win a CI war. Nam proved that pretty damn clearly. It's the morale of the army that makes or breaks a CI campaign, and the Sri Lankan army...well, it's not the worst, but it's not the best, either. The war was mostly fought on the Tamils' terms, with the army just trying to keep up.
The Tamils started ambushing army patrols around Jaffna, their key city, in 1983. By 1987 the Indian Army landed and pretty much forced the Tigers to sign a peace deal. The Tigers decided that they were better off not trying to fight the Indian Army, so they did. The Indians, who knew they'd gotten into a real bad mess, paddled home before the ink was dry on the peace treaty. The Tamils only waited till the Indian Army sailed home before restarting the war.
This was their high point: the early 1990s. They did a classic bit of power projection across the straits by assassinating Rajiv Gandhi in 1991 just when he was about to become Prime Minister of India, because they didn't like his anti-Tiger policies. Just to keep things fair and not show any favoritism, they also assassinated the Prime Minister of Sri Lanka in 1993.
The Sri Lankan army had its best moment when it captured Jaffna in 1995. This wasn't guerrilla warfare, it was classic massed armor attack against fortified positions. The US had a hundred-odd military advisors helping the Sri Lankan army by this time, and it showed. But the Tigers are cold-blooded, flexible fighters. Once they realized they'd lost the conventional war, they went back to unconventional warfare, setting off suicide bombs in the Sinhalese cities down south and ambushing army patrols. Soon they had the army bottled up in the Jaffna peninsula and were pressuring the long supply lines all the way down the island.
In 1996 they set off what was one of the bloodiest single terrorist attack in history, a big huge truck bomb they drove right into the Central Bank in Colombo. At least a hundred people died, and 1,500 were injured. This was the kind of thing that made your ordinary Sri Lankan real tired of the whole damn war.
By 2002 even the Tigers were tired. They couldn't destroy the army, and the army sure as Hell hadn't destroyed them. The Indians were getting tired of taking care of a half-million Sri Lankan refugees, the CIA wanted the whole mess done with, and there was a new peacenik administration in power in Sri Lanka. All around the world, guerrilla ethnic armies were winding down and switching to politics. The Tamils saw the way things were going and got the best deal they could.