GENEVA (AP) — As nations mount an offensive against the Islamic State militants that have gained a stronghold in Iraq and Syria, a U.N. human rights commission emphasized Tuesday that the Syrian President Bashar Assad’s government has committed the bulk of atrocities in the civil war.

The head of the commission, Brazilian diplomat and scholar Paulo Sergio Pinheiro, told the U.N.’s top human rights body that the government’s killing of civilians — often through the use of ubiquitous checkpoints — exceeds the crimes against civilians perpetrated by the militants and other anti-government armed groups.