By Patrick Markey and Raheem Salman
BAGHDAD (Reuters) - Mortar rounds hit an Iraqi Sunni Muslim mosque and a bomb exploded in a Shi'ite mosque on Friday in attacks that killed eight and fuelled tensions a day before provincial elections.
Troops also fired on Sunni Muslim protesters in Kirkuk in clashes that killed at least two people during a rally against Shi'ite Prime Minister Nuri al-Maliki.
Saturday's ballot will test Iraq's political stability, with Maliki's fragile government already caught up in a crisis over power-sharing among Shi'ite, Sunni and ethnic Kurds more than a year after the last U.S. troops left.
Bombings and suicide attacks have surged since the start of the year, with a local al Qaeda wing stepping up its campaign to try to trigger large-scale confrontation among Iraq's mix of Shi'ite and Sunni Muslims and Kurds.
The vote will measure the political muscle of Maliki's Shi'ite coalition and his Sunni rivals who are jockeying for position before the 2014 parliamentary vote where the prime minister may seek a third term.
More than a dozen candidates have been killed during the campaign, and voting has been suspended in two mainly Sunni provinces because officials said they could not guarantee security.
In the worst attack on Friday, police said several mortar rounds landed outside a Sunni Muslim mosque in a village near Khalis town during prayers, killing seven people and wounding a dozen more, police said.
A bomb placed inside a Shi'ite mosque in Kirkuk, 170 km (100 miles) north of the capital, also killed one and wounded 12 more just as worshippers were leaving, officials said.
"It appears the bomb was hidden there before prayer time and when the worshippers were leaving, it exploded," said sheikh Raad al-Sakhri, the preacher of mosque and a representative of anti-U.S. cleric Moqtada al-Sadr.
A day earlier, a suicide bomber blew himself up on Thursday evening inside a Baghdad cafe in a mainly Sunni neighborhood, killing a least 32 and wounding dozens more in one of the worst single attacks in the Iraqi capital this year.
Iraqi troops clashed with Sunni protesters in Kirkuk after demonstrators approached a checkpoint following Friday prayers, protest leaders and security officials said.
Security officials said troops were attacked by protesters. But protest leaders dismissed reports they were armed, blaming soldiers for the death of a protester and a soldier.
"One demonstrator was killed and three wounded and one soldier killed and three wounded in exchange of fire between some worshippers and some security elements in a checkpoint close to their mosque," a senior security official said.
Since U.S. troops left in December 2011, Maliki's Sunni and Kurdish partners have accused him of reneging on power-sharing agreements and consolidating his authority at their expense.
Thousands of Sunni protesters have taken to the streets in western provinces since December to demand reforms to address the discrimination they say their sect faces from the Shi'ite-led government in Baghdad.
Many Sunnis feel they have been sidelined by the country's Shi'ite leadership since the fall of Saddam Hussein after the 2003 invasion. Others say they have been unfairly targeted for arrest by security forces under tough anti-terrorism laws.
Voting in Anbar and Nineweh provinces has been suspended for as long as six months because local officials said they were unable to guarantee security there. But election authorities have suggested that voting may go ahead in a month's time.
Washington has urged the government to reconsider the decision and Iraqi Sunni leaders have warned that suspending elections may help push protesters into the hands of hardline Sunni Islamists.
Al Qaeda is already regaining ground in Iraq, especially in the western desert near Syria's border, where it has benefited from the flow of Sunni fighters opposing Syrian President Bashar al-Assad. It is also seeking to tap into Iraqi Sunni discontent.
(Reporting by Raheem Kareem, a Reuters reporter in Diyala and Mustafa Mahmoud; Writing by Patrick Markey; Editing by Alison Williams)