BELGRADE - Unexploded cluster bombs still threaten thousands of Serbian civilians almost 10 years after they were dropped during NATO's air war over Kosovo, an independent report said Tuesday.

An unexploded cluster bomb (REUTERS/Ruben Sprich) "During the 1999 NATO bombing campaign, U.S., British and Dutch forces dropped at least 37,000 sub-munitions on Serbian territory," the Cluster Munition Coalition (CMC) said in a statement.

"According to the survey published by Norwegian People's Aid, a CMC member, a decade on unexploded cluster bomblets continue to pose a threat to tens of thousands of local inhabitants," it added.

There were 2,547 unexploded bomblets located across Serbia, excluding its breakaway province of Kosovo, according to a report the CMC presented at a media conference in Belgrade.

The warning came in a statement that called on the Serbian government to sign up to the cluster bomb ban convention already backed by 95 other countries

The convention bans the use and stockpiling of cluster bombs and contains provisions on clearing unexploded cluster bombs and aiding victims.

"Serbia should sign the Convention on Cluster Munitions without delay, there is simply no reason not to and every reason to do so," CMC coordinator Thomas Nash said in a statement.

Contacted by AFP, Serbia's defence and foreign ministries declined to comment on the Balkan country's failure to sign the convention.

But the CMC statement noted that Serbia was one of the few affected countries to have used and produced cluster munitions, and that it has an outdated stockpile of the weapon.

"I am disgusted by the attitude of my government," said Dejan Dikic, a civilian victim from Serbia.

"I can't understand it," Dikic said, adding: "All the survivors in Serbia feel the same, we need support and the government is turning its back on us."

NATO's 1999 bombing campaign was launched against Yugoslavia, then made up of Serbia and Montenegro, to halt a violent crackdown on separatist Kosovo Albanians by forces loyal to late president Slobodan Milosevic.

Kosovo proclaimed unilateral independence from Serbia in February 2008.

It is now recognized by 56 countries including the United States and 22 of the European Union's 27 member states. Serbia is backed by its old ally Russia in its opposition to the move.