Last night's bombing in the town of Balad Ruz also wounded 68 people, according to Ahmed Alwan, a doctor at the general hospital of Baquba, the provincial capital of Diyala.
"The final toll from Friday's bombing is 30 dead and 68 wounded. All the dead are men, but the wounded include three women and two children," Alwan said.
Balad Ruz police chief Major Ahmed al-Tamimi had given yesterday a toll of 25 dead and 70 wounded "when a suicide bomber detonated a belt filled with explosives at a coffee house in the centre of the city."
Suicide bombings across Iraq have fallen since 2008 when Diyala province was an Al-Qaeda stronghold. Although the militants have lost ground, the province remains one of the most restive since the 2003 US-led invasion.
Yesterday's attack took place in a region with a Kurdish Shiite majority.