By Wisam Mohammed
BAGHDAD (Reuters) - Gunmen killed three Iraqi election candidates in separate incidents on Thursday, two days before Iraq holds provincial polls that will test the war-weary country's fragile democracy.
Hazem Salem Ahmed, a Sunni Arab candidate from the National Unity List, was shot outside his home in the volatile northern city of Mosul, where minority Kurds and Sunnis are facing off and where al Qaeda and other insurgents have made a last stand.
In Baghdad's Amiriya district, gunmen killed candidate Omar Faruq al-Ani, a member of the Iraqi Islamic Party, near his home after a campaign rally.
Candidate Abbas Farhan from the National Movement of Reform and Development was gunned down in a village near the town of Mandili in Diyala Province, northeast of Baghdad, near the Iranian border, also after a campaign rally.
The rash of shootings brought to at least five the number of candidates slain before the polls. The election will select local leaders in 14 out of 18 provinces and could alter Iraq's delicate balance of power.
Sunni Arabs, a minority disempowered after the U.S.-led invasion toppled Saddam Hussein in 2003, are likely to gain power in some areas after boycotting elections in 2005.
But they are also competing amongst themselves in western Iraq as upstart groups, many associated with a neighbourhood guard movement that stood up to Islamist al Qaeda, challenge more established parties.
Shi'ite parties, including those backed by Prime Minister Nuri al-Maliki, are competing across the largely Shi'ite south and other areas.
The lead-up to the polls has generally been less violent than some U.S. and Iraqi officials had feared.
U.S. military spokesman Brigadier-General David Perkins said there were nine attacks on Wednesday, when soldiers, displaced people and prisoners voted in early polls, compared to an average 92 attacks a day in January 2005 when Iraq last voted.
"There are obviously people, al Qaeda, other terrorists, special groups, criminals, who see the progress of democracy as a threat to them. They want an Iraq that is ruled by fear," Perkins said.
"So we are very focussed on making sure they cannot disrupt the democratic process here in Iraq."
Security will be tight for the polls, with a curfew and a vehicle ban intended to discourage car bomb attacks.
Iraqi security forces are taking the lead and U.S. forces, preparing to withdraw by the end of 2011, are standing by to provide air support if needed.
As violence drops sharply across Iraq, candidates have embraced a colourful and vocal campaign, plastering posters across the country, holding festive rallies in parks and floating balloons carrying their names.
There have been hiccups. Four candidates from a list backed by followers of anti-American Shi'ite cleric Moqtada al-Sadr were arrested briefly on Thursday.
A government spokesman said the men were held after a fracas at a checkpoint near northern Baghdad's Shula neighbourhood. The candidates -- independents supported by Sadr followers -- said the arrests took place at a campaign rally.
"The four came and started a fight at a checkpoint, abusing the soldiers verbally and then beat one of them. After that they were arrested," said Baghdad security spokesman Major-General Qassim Moussawi.
He later said the men had been released.
Mazen al-Saadi, head of the Sadr office in Shula, said the four were arrested along with dozens of followers while staging a campaign rally in the area.
Sadr's followers have been on the back foot heading into Saturday's vote after a government crackdown on their Mehdi Army militia last year.
But they are hoping to claim a greater share of local power in the capital after largely skipping the last provincial elections in January 2005.
(Additional reporting by Deborah Lutterbeck in Washington; Writing by Missy Ryan and Peter Graff; Editing by Michael Christie and Angus MacSwan)