Iran announced on Friday that all six land border crossings with Iraq are temporarily closed until further notice due to congestion, hot weather, and lack of facilities to ensure passengers' health and security, according to the official news agency IRNA.

The closure was announced by Majid Mir-Ahmadi, head of Iran's Arbaeen Central Headquarter, as the land border crossings have been jammed by millions of Iranians heading to neighboring Iraq for the annual Arbaeen pilgrimage.

The border crossings are Mehran, Khosravi, Shalamcheh, Chazzabeh, Tamarchin and Bashmaq.

Iranian senior officials, including President Ebrahim Raisi, are following up on the reopening of the border crossings.

During Arbaeen ceremonies, millions of people from across the world travel to Iraq to walk by foot between the Iraqi cities of Najaf and Karbala, among whom, Iranians constitute a vast majority.

This year's Arbaeen pilgrimage comes after two years of the COVID-19 pandemic restrictions.

According to estimates, around five million Iranians are heading to Iraq for the pilgrimage, resulting in traffic jams and chaos at the border crossings in Iran's western provinces of Ilam and Khuzestan.