A top official of the United Nations Mine Action Service has appealed to the world to stop using cluster munitions.
UNMAS director Ilene Cohn spoke to NHK on Friday while visiting Tokyo.
Both Russia and Ukraine have been using cluster bombs since Russia's invasion in February 2022, with the United States supplying them to Ukraine's military.
The bombs are highly lethal but many can remain unexploded, posing a deadly risk for civilians for years after a conflict.
The Convention on Cluster Munitions bans the production and use of the weapons, but the three countries have not signed up to the agreement.
Cohn called their use "a violation of international customary humanitarian law," and requested all parties in conflicts to immediately stop using them.
She cited growing concerns that the use of the bombs in Ukraine would undermine the spirit of the treaty, and noted the importance of focusing on the long-term impact of "indiscriminate" weapons on civilians.
The director stated that they are also used in Myanmar and Syria, and casualties are increasing.
She called for all countries including Japan to work harder for the abolition of the munitions.