Rights group Amnesty International says there is evidence of what it calls an emerging pattern of indiscriminate attacks against civilians by the Syrian army.

Amnesty released a report Wednesday based on its investigation earlier this month in Idlib, Jabal al-Zawiya and north Hama. The group says government forces are routinely shelling towns and villages with imprecise weapons that should not be used in residential areas.

Amnesty International reiterated calls made by rights groups for the United Nations Security Council to refer the situation in Syria to the International Criminal Court for probes into possible war crimes.

It also warned that opposition fighters may also turn to indiscriminate attacks, and urged rebel groups to communicate to fighters that such violations will not be tolerated.

The report comes days after a U.N. panel presented a report blaming both sides for increasing the number of attacks against civilians.

The U.N. commission of inquiry said that while both government and anti-government forces committed war crimes, the abuses by opposition forces did not reach the “gravity, frequency and scale” of those carried out by pro-government fighters.