The U.N. mission in Afghanistan says the number of children killed or wounded in the country's conflict has increased in the first nine months of 2016, compared to the same period last year.

A report by UNAMA released Wednesday says the mission documented a total of 2,461 children's casualties in 2016 — 639 deaths and 1,822 wounded.

That's a 15 percent increase, compared to the January-September period in 2015.

UNAMA says it's deeply concerned over the continuing increase in child casualties, which have risen since 2013.

Between Jan. 1 and Sept. 30, UNAMA documented 8,397 conflict-related civilian casualties — 2,562 deaths and 5,835 wounded.

That's a 1 percent decrease in overall civilian casualties, compared to the same period in 2015, though ground fighting is still the major cause of deaths.