Factbox: Five facts about Kosovo-Serbia relations

PRISTINA (Reuters) - The International Court of Justice will announce Thursday an advisory opinion sought by Serbia on the legality of Kosovo's 2008 declaration of independence.

Here are five facts on the strained relations between Serbia and its former province of Kosovo:

* As wars mark the collapse of Yugoslavia, writer Ibrahim Rugova becomes president of the self-proclaimed republic of Kosovo in 1992 in clandestine elections as ethnic Albanians start building parallel institutions.

* In 1998 a guerrilla insurgency of the separatist Kosovo Liberation Army gathered pace. The KLA seized swathes of land and war intensified against the Yugoslav army and police. NATO bombed to end a Serb crackdown on ethnic Albanians and Serb forces eventually left.

* Leaders in Belgrade were indicted for war crimes committed by Serbs during the counter-insurgency when about 800,000 Albanians were driven from their homes and another 10,000 were killed by Serb forces.

* In 2008 Kosovo's Albanian majority passed a declaration of independence that was rejected by 120,000 Serbs in Kosovo who are both financially and politically supported by Belgrade.

* In protest, Serbia blocked the border to Kosovo and does not allow goods and vehicles with Kosovo papers to enter its territory. Its officials are typically instructed to boycott meetings where Kosovo officials are present.

(Editing by Janet Lawrence)