The United Nations children's agency says civilian casualties caused by landmines and explosive ordnance more than doubled in Myanmar last year. This comes as fighting between the military and ethnic forces has been intensifying.

Data from UNICEF shows there were 1,052 such casualties last year, up from 390 the previous year. Children made up more than 20 percent of the victims.

The conflict in Myanmar has been escalating in recent months. Ethnic armed forces in the northern state of Kachin are waging a fierce offensive and have seized land and military strongholds near the border with China.

Landmines are especially common where fighting is fiercest. Military fighter jets have also dropped cluster bombs.

UNICEF says all parties to the conflict must focus on ensuring the safety of civilians, particularly children. The agency is calling for "immediate steps to halt the use of these indiscriminate weapons."