Sistani warns against foreign meddling in Iraq protests
"No person or group, no side with a particular view, no regional or international actor may seize the will of the Iraqi people and impose its will on them," Sistani said in his weekly sermon read by a representative in the Shia holy city of Karbala.
It comes after comments by Iran's supreme leader Ayatollah Ali Khamenei on Wednesday in which he urged protesters in both Iraq and Lebanon to pursue their demands through "legal frameworks".
Iraq has close but complicated ties with neighbouring Iran but also with Tehran's sworn foe Washington.
Since rallies against corruption and unemployment broke out on 1 October, demonstrators and their detractors have accused each other of being backed by outside actors.
More than 250 people have been killed and 10,000 wounded in the last month as the protests intensified into calls for the "downfall of the regime."
Sistani on Friday condemned the violence and said Iraq must not be dragged into the "abyss of infighting."
"I urge the relevant parties not to push armed forces in how they deal with the strikes and peaceful protests," he said.
Paramilitary factions have widespread influence in Iraq but their clout has been opposed by protesters over the past month.
Rival groups have taken to the streets in recent days to flex their muscles.