This is stated on the official page of the Iraqi government on Twitter.
Commander-in-Chief PM @AdilAbdAlMahdi declares 3-days of national mourning starting today to honor the martyrs who were assassinated by US forces in Iraq earlier this week.
- Government of Iraq - الحكومة العراقية (@IraqiGovt) 4 janvier 2020It is specified that the mourning is declared from Saturday, January 4.
Earlier it was reported that mourning events were held in Baghdad in connection with the death of Suleymani and Abu Mahdi al-Muhandis.
They died in a U.S. missile attack on the night of January 3 near Baghdad Airport.