A human rights group says Islamist militants who control northern Mali are using hundreds of child soldiers, some as young as 11.

Human Rights Watch says the children are being used — in violation of international law — both for military purposes and to enforce the militants' harsh version of Sharia, or Islamic law.

It says residents of northern Mali report seeing children between 11 and 17 receiving weapons training and manning checkpoints. The residents say young teens conduct foot patrols for the Islamic police and have beaten women on the street for failing to cover their heads.

The report, released Tuesday, also details amputations, floggings, and destruction of religious sites carried out by the militant groups.

The rights group says it based its report on interviews with nearly 100 witnesses who have fled northern Mali, or who remain there and talked by phone.

The U.N. Security Council has expressed alarm at the situation, most recently on Friday. Germany's U.N. ambassador, Peter Wittig, said the Council is concerned about “increasing entrenchment of terrorist elements” and the deterioration of security in the region.

“They express their grave concern about the violations of human rights perpetrated by rebel and extremist groups in the north of Mali.”

Militant groups Ansar Dine and the Movement for Oneness and Jihad in West Africa (MUJAO) seized control of northern Mali earlier this year, in the confusion that followed a military coup in Mali's capital, Bamako.

Both groups are believed to have close links to al-Qaida in the Islamic Maghreb.

Human Rights Watch says the groups appear to coordinate their actions. It also says the majority of commanders are non-Malian, coming from Mauritania, Algeria, Western Sahara, Senegal, Tunisia and Chad.