The Tamil Tigers, according to Wikipedia:

The Liberation Tigers of Tamil Eelam (LTTE, Tamil: தமிழழவிடுதலைப்புலிகள் ISO 15919: tamiḻ iiḻa viṭutalaip pulikaḷ), commonly known as the Tamil Tigers, is a militant terrorist organization that has waged a violent secessionist campaign since the 1970s to secede from the Sri Lankan state in order to create a separate Tamil state in the north and east of the island. This campaign has developed into the Sri Lankan Civil War, one of longest running armed conflicts in Asia. Due to the tactics employed by the Tamil Tigers, including the extensive use of suicide bombing and their recruitment of child soldiers, they are currently proscribed as a terrorist organization by 32 countries. The Tamil Tigers are headed by their founder, Velupillai Prabhakaran.

The Tamil Tigers are notorious for their well-developed militia cadre, atrocities against Muslim and Sinhalese civilians, and high profile attacks, such as the assassination of several high ranking Sri Lankan politicians, and the former Prime Minister of India Rajiv Gandhi. They also have the distinction of introducing suicide bombings as a tactic, and have carried out more suicide bombings than Hamas, Islamic Jihad, and al-Qaeda combined. The LTTE have repeatedly been accused of recruiting child soldiers. The LTTE are the only rebel organization with aircraft.

In January 2009, Canada and the EU notably refused to take the group off its terrorist list, even while the EU agreed to remove the Mujahideen Organization of Iran. The U.S. has had the Tamil Tigers on its terrorist list since the 1990s.

European states agreed on Monday to remove exiled Iranian opposition group the People’s Mujahideen Organization of Iran (PMOI) from an EU list of banned terrorist groups, an EU official said.

The official confirmed that EU foreign ministers approved a decision to take it off a list that includes Palestinian Hamas and Sri Lanka’s Tamil Tigers.

The PMOI is the group which exposed Iran’s covert nuclear program in 2002. It began as a leftist-Islamist opposition to the late Shah of Iran and has bases in Iraq.1

Waving today in the march were the flags of the U.S. and Canada, among others.