The World Health Organisation (WHO) said children aged 12 and over should wear masks to help tackle the COVID-19 pandemic under the same conditions as adults.
It added that children between six and 11 should wear them on a risk-based approach.
Children aged 12 and over should particularly wear a mask when a one-metre distance from others cannot be guaranteed and there is widespread transmission in the area, the WHO and the United Nations Children's Fund (UNICEF) said in a document on the WHO website dated August 21.
Whether children between six and 11 should wear masks depends on a number of factors, including the intensity of transmission in the area, the child's ability to use the mask, access to masks and adequate adult supervision, the two organisations said.
The potential impact on learning and psycho-social development, and the interactions the child has with people at high risk of developing serious illness, should also play a role.
Children aged five years and under should not be required to wear masks based on the safety and overall interest of the child, the WHO and UNICEF said.
Studies suggest older children potentially play a more active role in the transmission of the new coronavirus than younger children, the WHO and UNICEF said, adding more data was needed to better understand the role of children and adolescents in the transmission of the virus, which causes COVID-19.
The WHO first advised people to wear masks in public on June 5 to help reduce the spread of the disease, but had previously not issued specific guidance for children.
More than 23 million people have been reported to be infected by the coronavirus globally since it was first identified in China last year.
Serbia PM Vucevic formally resigns, triggering deadline for new government
Six migrants dead, 40 missing in shipwreck off Italy's Lampedusa
Netanyahu says Gaza strikes are 'just the beginning'
NASA astronauts 'Butch and Suni' return to Earth
Zelenskyy calls for blocking Moscow's attempts to drag out war
