A group of Cambodian families whose children are recovering or have recovered from congenital heart diseases in Southwest China's Yunnan province, have donated hundreds of masks to China, helping Chinese hospitals fight against the novel coronavirus.

The masks were sent by Cambodian volunteers to Kunming, the capital of Yunnan province,on Tuesday, after a ceremony was held in Phnom Penh, Cambodia, a day earlier.

The 5,021 masks were donated by 86 families in Cambodia. Their children recovered from congenital heart diseases after free surgeries and treatment in Yunnan in the past two years.

Chinese medical teams have so far visited many provinces in Cambodia to give a free medical checkup for thousands of children with heart disease after both countries agreed in 2018 to conduct joint efforts to fight heart disease in the Southeast Asian country.

Demand for masks has increased exponentially in China due to the coronavirus outbreak.

Ban Chunsocheata, 10, with her mother, bought a pack of masks and sent them to volunteers.

"Chinese doctors saved my daughter and family. Although there are not so many masks we bought, we hoped we could lend our hands to help China fight against the novel coronavirus," she said.