The bombing in Sadr City, and another on Friday that hit a Shia mosque in the Baghdad neighbourhood of Shoula, "increase the resolve and determination" of Iraqi security forces, Abadi said.
In Sadr City, a frequent target for bombings, residents used vegetable carts to transport the wounded from the scene, video footage showed. Many of the at least 28 dead were children, according to the Ministry of Defence.
In response to the bombing in the neighbourhood named after his father, the prominent cleric Moqtada al-Sadr called on fighters with his militia, formerly the Mahdi Army but now known as the Peace Brigades, to be on standby to defend the capital.
"I call on the Government to be alert to the threat posed to Baghdad, rather than being busy collecting money," he said.
Sadr has been reasserting himself politically in recent weeks, holding a huge rally in the capital last week calling for reforms.
- Washington Post, Bloomberg