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BAGHDAD, Iraq — Iraq's most powerful Shiite cleric called for a global war against ISIS on Friday, a day after the prime minister said he would welcome Russian airstrikes against the group on his country's soil.

Grand Ayatollah Ali al-Sistani, who has a huge following and can often influence government thinking, was speaking through an aide after nationally televised Friday prayers.

Grand Ayatollah Ali al-Sistani is Iraq's top Shiite cleric. AFP - Getty Images, file

"Battle with Daesh is destined for all Iraqis," said Sistani, using an Arabic acronym for ISIS. "But it's not their battle alone but the whole world, because terrorists target with their dark ideology all humanity, its culture and morals."

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He added: "It's essential to join together all efforts and expand the parameters of countering this movement."

The United States has led airstrikes against ISIS in Iraq for more than a year, but Baghdad has repeatedly called for engagement and air support for Iraqi forces trying to regain territory against the ultra-hardline Sunni group.

Russia began bombing raids in Syria on Wednesday against groups fighting the forces of President Bashar Assad, which include ISIS.

Iraqi Prime Minister Haider al-Abadi said on Thursday his government would welcome Russian airstrikes against ISIS in Iraq.

Asked by France 24 television whether he had discussed airstrikes with Russia in his country, Abadi said: "Not yet ... It is a possibility. If we get the offer we will consider it and I would welcome it."