BAGHDAD, Jan 28: Insurgents bent on wrecking Sunday's landmark election killed 10 Iraqis and five US soldiers on Friday as the government announced the capture of two al Qaeda lieutenants.

The government imposed extraordinary security restrictions to try to safeguard the polls. Land borders were closed and travel between provinces was banned. An extended curfew was imposed in most cities from 7pm to 6am (1600-0300 GMT).

Iraqis began voting abroad. In Australia, exiles danced in the streets, proudly displaying blue ink on their fingers which showed they had cast the election's first votes.

"When I look at the ink on my finger - this is a mark of freedom," said Kassim Abood, outside a polling booth in a disused furniture warehouse in Sydney. Security was tight at polling venues in Syria, Jordan, and Turkey and police kept traffic away with roadblocks.

Guards with metal detectors searched everyone going into the stations. The cleric at Baghdad's top Sunni mosque broke with hard line religious leaders on Friday to urge worshippers to vote for the best candidate in Iraq's historic election two days away.

"The national assembly is going to happen. Each voter must choose the candidate he believes in," said Sheikh Moayed al-Adami, imam at Abu Hanifa mosque in the Sunni district of Adhamiyah.

"We must choose the best-suited people, the wisest, the most intelligent and patient," he said from his mosque, where a typical Friday prayer is filled with fiery rhetoric, often against the US presence in Iraq.

"The nation must choose the candidates who are of merit and deserve their vote." "Our rights have been damaged. We must choose the honest souls, the men of words and action," he said, alluding to the Sunni community in post-Saddam Hussein Iraq.

Al Qaeda's leader in Iraq, Abu Musab al-Zarqawi, has vowed to kill anyone who votes in a poll he says is designed to bring Iraq's "infidel" Shia majority to power. Iraq's minister of state for national security said two of the Jordanian militant's aides had been captured, including his alleged chief of operations in Baghdad, seized on Dec. 31.

In a statement, the government said the Baghdad operations chief, named as Salah Salman Idaaj Matar al-Luhaybi and also known as Abu Sayf, had met Zarqawi four times in December.

It said the second captured Zarqawi lieutenant, Ali Hamad Ardani Yasin al-Isawi, had met Zarqawi 40 times in the past three months and was caught west of Baghdad on Jan. 20.

In southern Baghdad, a car bomb exploded next to a police station, killing four Iraqi civilians, police said. A second car bomb detonated nearby shortly afterwards, close to a school that will be used as a polling station.

In the western city of Ramadi, a guerilla stronghold, six Iraqi soldiers were killed in ambushes, an Iraqi officer said. The US military said a soldier was shot dead in northern Baghdad. A roadside bomb killed an American soldier and wounded two others in the south of the capital.

Shias, who comprise 60 per cent of Iraq's population, are expected to cement their new political dominance through the polls. An alliance of candidates formed under the guidance of Iraq's top Shia scholar, Grand Ayatollah Ali al-Sistani, is almost certain to win the most votes.

Several leading Sunni Arab parties are boycotting the polls, saying the insurgency raging in Iraq's Sunni heart lands will make it impossible to vote there. The election is for a 275-member National Assembly that will oversee the drafting of a permanent constitution.

Jubilant Iraqi exiles cast their ballots in a "vote for freedom" on Friday and urged their compatriots in Iraq to defy insurgents and do the same. In the United States, Iraqi expatriates defied frigid temperatures and long trips to the polls to enthusiastically cast their votes across the eastern United States.

"I'm 39, but today, I'm just born," said Yaqoob Al-Awsa, a painter from Ann Arbor, Michigan, who was also celebrating his birthday. "This is the first day for me. I was almost crying."

In Irvine, California, a stream of Iraqis, including older men and women wearing headscarves went through metal detectors to vote. Talal Ibrahim, 52, originally from Baghdad, was the first to cast his ballot to a round of applause from poll workers.

"I'm very excited. I'm so happy. I think this is the least thing we can do for Iraq ... This is the start of a stable Iraq," said Ibrahim, a communications engineer. Lamaa Jamal Talabani, 60, who voted in Amman, said: "I have been dreaming of this day to tell my grandchildren that in the first election in the history of Iraq I was the first woman to vote."

"People should not be afraid to vote," said Nassima Barzani, 68, proudly clutching an Iraqi flag as she voted in Sydney, where Iraqis danced and sang in the streets.

In Iran, the largest centre for registered Iraqi voters aboard with about 61,000, queues formed outside a Tehran polling station. Many were women in traditional black chadors.

Iranian television repeatedly broadcast footage of Iraq's top religious authority Ayatollah Ali al-Sistani and called on Iraqis to vote for candidates he is thought to back.

"I am voting out of loyalty for my fellow countrymen, for our great Iraq, for those buried in mass graves and for our martyrs," a weeping Adel Mijbil Qawqaz said at a polling station in the United Arab Emirates.

In the snow-covered Stockholm suburb of Skarholmen, Iraqis queued before dawn to vote amid tight security. -Reuters / AFP