Also, U.S. commanders in Iraq said a roadside bomb claimed the life of another American soldier.
A statement said the soldier was killed Sunday when the bomb blew up near his patrol in western Baghdad. It's the seventh U-S combat fatality in the Baghdad area since Thursday.
Meanwhile, assailants blew up an electoral center Sunday in a town 12 miles south of Samarra and opened fire on a Turkoman political party office in Mosul, wounding three people, police said.
In Najaf, the country's leading Shiite cleric, Grand Ayatollah Ali al-Sistani, urged followers to turn out in large numbers for the Thursday balloting, in which voters will choose a 275-member parliament to serve a full four-year term.
But al-Sistani stopped short of openly endorsing the coalition of religious Shiite parties which swept the largest number of seats in the January election.
The Interior Ministry said the emergency measures will take effect early Tuesday and last until Saturday morning. The nighttime curfew will be extended by three hours, all international borders and airports will be closed and travel across provincial boundaries will be banned.
Additional forces have been sent to Ramadi and other insurgent trouble-spots to bolster security, the ministry said.
"We are very prepared for the elections and we are highly determined," Interior Minister Bayan Jabr told reporters.
The election will be the first under the new constitution ratified in a referendum Oct. 15 and will complete the steps toward democratization in Iraq following the ouster of Saddam Hussein's regime in the 2003 U.S.-led invasion.
Voting will begin Monday in military camps, hospitals and prisons for inmates who have not been convicted of any offenses. Iraqis living outside the country can vote starting Tuesday at special centers in 15 countries.
U.S. officials hope that establishment of a broad-based constitutional government will help calm the Sunni Arab-led insurgency and allow the United States and its coalition partners to begin drawing down troops next year.
The Americans are hoping for a strong turnout among Sunni Arabs, the community at the foundation of the insurgency. Many Sunnis boycotted the January election, sharpening communal tensions and fueling the insurgency.
However, U.S. commanders have also warned that the insurgency remains a threat to the new Iraqi government and that the reduction of coalition forces can take place only when Iraq's army and police are ready.
In Sulaimaniyah, President Jalal Talabani predicted that no party will win a clear-cut victory Thursday, forcing a coalition government such as the one currently in power.
A coalition of Shiite religious parties is expected to win the biggest bloc of seats again Thursday but probably fall short of the number they hold in the current parliament. Most Sunni Arabs boycotted the January election, but this time a number of Sunnis are in the race and are expected to win a strong bloc.
"Indications are that many Iraqis of various sectarian and ethnic lines will participate. I urge all Iraqis to go out and vote," U.S. Ambassador Zalmay Khalilzad said in Sulaimaniyah. "We need more cross sectarian and cross ethnic coalitions that are issue oriented.... We need a government that brings Iraqis together."
He expressed hope that "there will be more Sunni participation and that the turnout should be quite high."
In a fatwa, or religious edict, al-Sistani urged Shiites to vote for candidates "who can be trusted to protect their principles and safeguard their interests" in the next parliament.
"Toward this objective, splitting the vote and risking its waste must be avoided," he said.
Al-Sistani, who wields tremendous influence among the majority Shiite community, publicly endorsed the Shiite alliance. The lack of a strong, clear endorsement this time reflects his disappointment with the performance of Prime Minister Ibrahim al-Jaafari's coalition government and his wish not to be seen as directly involved in politics, associates have said.
In a statement Sunday, the election commission said it was investigating a five-fold increase in the number of new voters in Kirkuk, an oil-rich northern city that the Kurds would like to incorporate into their self-ruled region.
The statement did not mention any group by name but it appeared the increase could be an attempt by Kurds to pack the rolls ahead of the election.