Baghdad (CNN) -- Bombs struck Sunnis leaving a mosque and attending a funeral in Iraq on Friday, killing dozens amid festering tensions between Sunnis and Shiites.
At least 40 people were killed and 46 others wounded Friday in two roadside explosions outside a Sunni mosque in the Iraqi city of Baquba, police and health officials told CNN. Baquba, the largest city in Diyala province, is about 60 kilometers (37 miles) north of Baghdad.
That bombing was one of several attacks Friday, and came on the heels of a spate of sectarian violence in the Middle Eastern nation.
A roadside bombing in Amirya, a predominantly Sunni western Baghdad neighborhood, left 12 dead and 30 wounded, police officials told CNN.
Another roadside bomb in western Baghdad -- this time in al-Jamia -- went off outside the house of Sunni member of parliament Ahmed al-Massari, wounding two bodyguards Friday morning, police said. Al-Massari's brother was shot dead near his house in the Baghdad neighborhood of al-Bayaa on Thursday.
South of Baghdad, in the town of al-Madaan, police said at least eight people were killed and 25 were wounded Friday when a roadside bomb exploded at a funeral procession for the Sunni mayor of the town, who died Thursday.
Additionally, two people died in a pair of roadside bombing in Baghdad's Dora district, another Sunni neighborhood.
Overall, violence has dropped significantly in Iraq since the peak of sectarian violence, between 2005 and 2007. But tensions and violence, stirred in part by enmity between Shiites and Sunnis, have persisted since the U.S.-led invasion of Iraq in 2003.
Martin Kobler, the U.N. special representative for Iraq, called on leaders to protect civilians as another wave of bombings erupted this week, warning that the country "will slide backwards into a dangerous unknown if they do not take action."
"It is the responsibility of all leaders to stop the bloodshed in this country and to protect their citizens," he said.
"Small children are burned alive in cars. Worshippers are cut down outside their own mosques. This is beyond unacceptable. It is the politicians' responsibility to act immediately and to engage in dialogue to resolve the political impasse and put an end to this."
On Thursday, 11 people -- six in Baghdad and five in Kirkuk -- died in attacks in the two major Iraqi cities. The bloodiest attack was in the northern city of Kirkuk, where a suicide bomber detonated his explosive vest Thursday afternoon at the main entrance to a Shiite mosque, police said.
On Wednesday, bombings in Kirkuk and Baghdad left at least 29 people dead and 120 wounded, police said..
"Peace must come to this country now," Kobler said. "The people of Iraq have suffered enough."