FACTBOX - Newly-independent Kosovo, still claimed by Serbia

(Reuters) - NATO troops and United Nations police clashed with ethnic Serbs in the northern Kosovo flashpoint town of Mitrovica on Monday, in the worst violence in the territory since the Albanian majority declared independence last month.

Here is a brief profile of Kosovo, an ethnic crossroads in the heart of the Balkans and the cause of NATO's first "humanitarian war" in 1999.

HISTORY

* Kosovo was first inhabited by Illyrian and Thracian tribes, ruled by the Romans then populated by Slavs in the 6th century. It became part of the Kingdom of Serbia in the 13th century, with a mixed population of Serbs, Albanians and Vlachs. The Nemanjic dynasty made it Serbia's spiritual centre, giving lands to the Orthodox Church and building many monasteries.

ETHNIC MAKEUP

* Many Serbs left in the 500 years after the Ottoman Empire defeated the Serbs at the 1389 Battle of Kosovo. The Albanians, converts to Islam, grew in number. Mutual expulsions and migrations to and from Albania in the early 20th century changed Kosovo's makeup. Today, 2 million Albanians form 90 percent of the population. Some 120,000 Serbs remain in Kosovo, just under half in the northern enclave and the rest in scattered villages protected by NATO.

POLITICS & ECONOMY

* Landlocked and poor apart from mineral deposits, Kosovo was an autonomous region of socialist Yugoslavia and had effective self-government in 1974. Ethnic tensions escalated in the 1980s as Yugoslavia began to crumble and the economy deteriorated. Populist Slobodan Milosevic used Serb nationalism as a springboard to power in 1989, restricting Albanian rights. Strikes and violence led to Belgrade declaring a state of emergency in 1990, sending in the army and police.

Unemployment currently stands at more than 50 percent and the territory's infrastructure is in urgent need of investment.