U.N. officials will investigate the killing and wounding of children in Ukraine, Ethiopia and Mozambique, U.N. chief Antonio Guterres said on Monday in a report that found 2,515 children were killed and 5,555 maimed in global conflicts in 2021.

The annual "Children and Armed Conflict" report also verified the recruitment and use of 6,310 children in conflicts globally in 2021. Other violations it covers are abduction, sexual violence, school and hospital attacks and denial of aid.

It found the highest number of verified violations against children in 2021 were in Yemen, Syria, Afghanistan, the Democratic Republic of the Congo, Somalia, Israel and the Palestinian Territories.

Guterres said next year's report would include verified violations against children in Ukraine, Ethiopia and Mozambique.

His special envoy for children and armed conflict, Virginia Gamba, said that the two most concerning violations emerging from the conflict in Ukraine were the killing and maiming of children and attacks on schools and hospitals.

"So I think these two clearly are going to be very high," Gamba, who compiles the annual U.N. report, told reporters.

Russia invaded neigboring Ukraine on Feb. 24 and denies targeting civilian areas.

Without laying blame, U.N. human rights chief Michelle Bachelet said last week that as of July 3, 4,889 civilians had been killed in Ukraine, including 335 children, stressing that the real figure is likely much higher.

The children and armed conflict report includes a blacklist intended to shame parties to conflicts in the hope of pushing them to implement measures to protect children. It has long been controversial, with diplomats saying Saudi Arabia and Israel exerted pressure in recent years in a bid to stay off the list.

Israel has never been on the blacklist, while a Saudi-led military coalition was removed from the list in 2020 several years after it was first named for killing and injuring children in Yemen.

Israeli security forces killed 78 Palestinian children, maimed another 982 and detained 637 Palestinian children in 2021, according to the report, while in Yemen the Saudi-led coalition killed and maimed 100 children last year.

"Should the situation repeat itself in 2022, without meaningful improvement, Israel should be listed," Guterres wrote. He noted a "continued decrease in the number of child casualties" by the Saudi-led coalition in Yemen.

The Israeli and Saudi U.N. missions in New York did not immediately respond to a request for comment on the report.