A U.N. agency says it's gravely concerned about rising violence against children in northern Mali, since the area was seized by al-Qaida-linked Islamist fighters and Tuareg rebels following a March coup.

UNICEF says since the end of March at least 175 boys between 12 to 18 have been recruited into armed groups, at least eight girls were sexually assaulted and two teenage boys were killed by land mines and unexploded ordnance that maimed 18 others.

UNICEF spokeswoman Marixie Mercado told reporters Friday in Geneva that school closures in Mali have affected 300,000 children, making them more vulnerable to violence and recruitment as child soldiers.

She warned the numbers "are reason for alarm because they represent only a partial picture."