Campaigners reacted angrily on Monday to the removal of the Saudi-led military coalition in Yemen from a list of groups violating children's rights, in a report by UN Secretary-General Antonio Guterres.

"The Coalition to Support Legitimacy in Yemen will be delisted for the violation of killing and maiming, following a sustained significant decrease... due to air strikes," said the UN's newly-published annual report on children in conflict zones.

It said the toll had fallen since an agreement signed in March 2019.

The coalition intervened in 2015 in Yemen to support the government against Iran-backed Huthi rebels. It has been widely blamed for civilian casualties in bombing raids that campaigners say have pushed the country deeper into crisis.

Human Rights Watch denounced Guterres for dropping the coalition from the "list of shame," saying he was "ignoring the UN's own evidence of continued grave violations against children."

The Watchlist on Children and Armed Conflict said that "by absolving the Saudi- and Emirati-led coalition of any responsibility for killing and maiming children in Yemen, the UN Secretary-General has left children vulnerable to further attacks."

It said the coalition was responsible for the death or injury of 222 children in Yemen last year.

Inger Ashing of Save the Children called it a "shocking decision" by Guterres.

A child in a Yemeni camp in the Khor Maksar district of the city of Aden on May 5, 2020
A child in a Yemeni camp in the Khor Maksar district of the city of Aden on May 5, 2020 AFP / Saleh Al-OBEIDI

But the secretary general's envoy for children and armed conflict, Virginia Gamba, said the UN had come "under no pressure" from Saudi Arabia and that the removal from the list was based on data.

In 2016 the coalition was briefly included on the annual list before a threat by Saudi Arabia to cut off funding to UN programs forced a reversal.

The following year, after Guterres assumed the UN leadership, the coalition was placed in a sub-section of the report created for those making efforts to avoid deaths of children. It remained there in 2018 and 2019.

The report, which reviews several conflicts worldwide each year, said 4,019 children were verified as having been killed and more than 6,000 maimed in 2019.

The numbers were similar to 2018, according to the UN.

The report partially removed the Myanmar armed forces, called Tatmadaw, from the blacklist.

They no longer appear for recruitment of children but remain on the list for their death, mutilation and rape.

Guterres cited "a continued significant decrease in recruitment, ongoing prosecutions and an agreement to continue to trace and release cases."

Save the Children described the move as "premature and dangerous."