The UN's highest court has ruled that Serbia did not commit genocide against Croats during the Balkan wars of the early 1990s.

"Croatia has failed to substantiate its claim that genocide was committed" by Serbia, Judge Peter Tomka said.

He was reading the verdict in the landmark case at the Hague-based International Court of Justice.

A 17-judge bench ruled that the acts committed by the Serbs had not intended to "destroy" the Croatian ethnic group in certain areas of Croatia claimed by Serb secessionists, but to "move them by force."

The ICJ also dismissed a claim of genocide by Croatia against Serbs during an offensive to take back territory in the mid-1990s.

Croatia brought Serbia before the ICJ in 1999 on genocide charges linked to Croatia's war of independence in 1991-95 following the breakup of the former Yugoslavia.

Serbia was accused of ethnic cleansing as a "form of genocide", leading to large numbers of Croats being displaced, killed or tortured and their property being destroyed.

Croatia had sought financial compensation.

About 20,000 people died in the conflict, one of several bloody wars that shook the Balkans in the 1990s.

Belgrade responded with a counter-suit in 2010, saying 200,000 ethnic Serbs were forced to flee when Croatia launched a military operation to retake its territory.

Following Zagreb's counter-offensive, called Operation Storm, the proportion of ethnic Serbs in Croatia shrank from 12% to 4%.