Iraqi Prime Minister Haider al-Abadi has warned of potential attacks on Iraq during the Arbaeen pilgrimage.

Undeterred by the threat that ISIS militants pose, millions of pilgrims gather each year in the Iraqi holy city of Karbala to observe Arbaeen, which marks the end of a 40-day mourning period for the martyrdom of Imam Hussein (AS), the grandson of the Prophet Mohammad (S), in 680 AD.

During the Iraqi cabinet regular session on Tuesday, Abadi warned of “cowardly” terror attacks that may target various cities in the Arab countries.

“Boosting relations among countries will significantly reduce the conflicts,” he added.

Meanwhile, military operations are underway in Anbar since October 22 in order to eradicate ISIS terrorists.

On Friday, Sayid Ahmed al-Safi, a representative to Iraq’s most prominent Shia cleric Ayatollah Sistani, said he hoped that Iraqi forces will fully eradicate ISIS terrorists from Iraq.

He also called on pilgrims to maintain calm and safe atmosphere of the Arbaeen pilgrimage.

Safi went on to warn of potential ISIS attacks against Shia processions.

The Arbaeen pilgrimage is the world’s largest public gather that is held every year. Last year about 20 million people took part in the ceremony.

Many pilgrims choose to make the journey on foot, despite the dangers of travelling near ISIS-controlled areas in the country.