Mortar fire and bombs targeting worshippers killed nine people and injured 29 others on Friday in two attacks north of Baghdad shortly after noon prayers.
The fresh violence came a day after a suicide bombing on a Baghdad cafe killed 36 people and wounded dozens of others.
Police said the first attack came just after Friday prayers as the worshippers were leaving the Sunni mosque of al-Muthana in Khalis, killing seven worshippers and injuring 14 others.
Khalis, a former stronghold of Sunni insurgency, is 80 km (50 miles) north of Baghdad. Police said part of the mosque was destroyed in the mortar attack.
In the oil-rich city of Kirkuk, police said a roadside bomb exploded among Shiite worshippers as they were heading home after prayers in al-Tamimi mosque, killing two worshippers and wounding 14 others.
Medics in nearby hospitals confirmed the dead toll. All officials spoke on condition of anonymity because they were not authorised to speak to reporters.
Violence has been on the rise ahead of provincial elections set for Saturday. The voting is for local officials in several provinces across the country, including the capital, Baghdad. Authorities have been pledging to bolster security ahead of the elections.