In this May 13, 2019 file photo, a Yemeni child who fled fighting between Yemen's armed rebels, known as the Houthis, and pro-government forces in Hodeida, is pictured at a makeshift camp in the district of Abs, in Yemen's northwestern Hajjah province. (ESSA AHMED / AFP)

NEW YORK - More than 8,500 children were used as soldiers last year in various conflicts across the world and nearly 2,700 others were killed, the United Nations said on Monday.

UN chief Antonio Guterres' annual report to the Security Council on children and armed conflict covers the killing, maiming and sexual abuse of children, abduction or recruitment, denial of aid access and targeting of schools and hospitals.

The COVID-19 pandemic aggravated existing vulnerabilities of children, including by hampering their access to education, health and social services, limiting child protection activities and shrinking safe spaces

The report verified that violations had been committed against 19,379 children in 21 conflicts. The most violations in 2020 were committed in Somalia, Democratic Republic of the Congo, Afghanistan, Syria and Yemen.

It verified that 8,521 children were used as soldiers last year, while another 2,674 children were killed and 5,748 injured in various conflicts.

ALSO READ: Saudi-led coalition asks UN to share details of child deaths in Yemen

The report also includes a blacklist intended to shame parties to conflicts in the hope of pushing them to implement measures to protect children.

In an effort to dampen controversy surrounding the report, the blacklist released in 2017 by Guterres was split into two categories. One lists parties that have put in place measures to protect children and the other includes parties that have not.

Verified cases of abduction and sexual violence against children increased alarmingly by 90 percent and 70 percent, respectively. Abduction is often combined with the recruitment and use of children and sexual violence, according to the report.

Grave violations affect boys and girls differently. While 85 percent of children recruited and used were boys, 98 percent of sexual violence was perpetrated against girls. Sexual violence remained vastly underreported, owing to stigmatization, cultural norms, absence of services and safety concerns, according to the report.

READ MORE: UN report: Conflicts kill and hurt a record 12,000 children

The COVID-19 pandemic aggravated existing vulnerabilities of children, including by hampering their access to education, health and social services, limiting child protection activities and shrinking safe spaces.

The socioeconomic impact of the pandemic exposed these children to grave violations, notably recruitment and use, abduction and sexual violence. Attacks on schools and hospitals, and their military use, exacerbated the plight of children.

The protection of children affected by armed conflict is crucial to preventing conflict and sustaining peace, according to the report, adding that national and regional stakeholders should develop and expand initiatives to prevent grave violations.