Blasts rocked two Sunni mosques in central Iraq Monday, amid fears of renewed sectarian strife following Saudi Arabia's execution of a prominent Shiite cleric, police and medics said.

Groups of men wearing military uniforms detonated explosives at two Sunni mosques overnight in the Hilla region, south of Baghdad, and a muezzin -- the person appointed to recite the Muslim call to prayer -- was shot dead near his home in Iskandariyah, the sources said.

In Hilla, about 80 kilometres (50 miles) south of the capital, a police officer said the Ammar bin Yasser mosque in Bakerli neighbourhood was bombed after midnight.

"After we heard the explosion, we went to its source and found that IEDs (improvised explosive devices) had been planted in the mosque," the captain said.

"Residents said a group of people with military uniforms carried out this operation," he said, adding that 10 houses were also damaged by the explosion.

The Al-Fateh mosque in a village called Sinjar, just outside Hilla, was also damaged in similar circumstances.

The police captain said three or four men in military uniforms were involved that bombing.

"They took advantage of the cold weather, there was nobody outside," he said.

A medical source in Hilla said three people were wounded in the explosions.

There was no claim of responsibility for the incidents. Iraq often sees sectarian attacks by rival Sunni and Shiite militants.

The execution in Saudi Arabia of dissident Shiite cleric Nimr al-Nimr on Saturday prompted an angry reaction from Shiite political and religious figures in Iraq.

Decrying the execution, Iraqi Prime Minister Haider al-Abadi said that "the liquidation of opposition figures will only bring more destruction upon governments and people."