United Nations High Commissioner for Human Rights Navi Pillay on Monday condemned the rampant use of torture in detention facilities across Syria by government forces and some armed opposition groups.

Pillay's remarks came after her office issued a paper that describes a broad pattern of torture and ill-treatment against individuals by government and some armed groups.

"Our findings confirm that torture is being routinely used in government detention facilities in Syria, and that torture is also used by some armed groups," She said in a statement.

"In armed conflict, torture constitutes a war crime. When it is used in a systematic or widespread manner, which is almost certainly the case in Syria, it also amounts to a crime against humanity," Pillay added.

The UN human rights chief urged all sides to immediately halt the use of torture and ill-treatment, and to release all those who have been arbitrarily detained in conditions that clearly breach international human rights standards.