A police colonel reported an initial toll of seven killed and at least 15 wounded for the blast, which went off near Abdel Majid hospital
The accident was being investigated, but initial reports said it was caused by electrical contact
The blast came a day after a suicide bombing claimed by IS killed at least 15 people in Baghdad's Kadhimiyah neighbourhood
The Shia form a majority in Iraq but Sunnis are predominant in northern and western provinces, including Salahuddin where the mausoleum is located
A suicide bomber detonated an explosives-laden minibus in a Baghdad shopping district
A second bomber entered the shrine with nine gunmen targeting security forces as well as families gathering to celebrate Eid
This, after lawmakers again failed to approve new cabinet ministers