BAGHDAD, Iraq – Troops were in place, the borders were closed, and the ballots were ready yesterday on the eve of Iraqi parliamentary elections that America hopes will build democracy and set the stage for American troops to begin returning home.

With Sunni insurgent groups promising not to attack the polls, voter turnout was expected to be high.

However, police arrested two suspected insurgents carrying 72 bombs, police Lieutenant Colonel Ahmed Hajoul said. He said the pair said they planned to hide the bombs last night in the largely Shiite city of Hillah to explode when the polls opened.

A loud explosion was also heard in central Baghdad shortly before 1 a.m. today, hours after police said several mortar shells exploded in southwest Baghdad, setting some shops on fire.

There were also signs of the sectarian tensions that threaten the nation’s future and the Bush administration strategy: Angry Shiites protested what they considered to be a televised slur on the country’s religious leadership, and rumors spread of ballots smuggled in from Iran.

Nevertheless, most of Baghdad’s streets were eerily quiet yesterday, with police strictly enforcing a traffic ban.

Up to 15 million Iraqis were to choose 275 members of the new parliament from among 7,655 candidates running on 996 tickets, representing Shiite, Sunni, Kurdish, Turkomen, and sectarian interests across a wide political spectrum. Iraqis do not vote for individual candidates, but instead for lists – or tickets – that compete for the seats in each of the 18 provinces.

Some preliminary returns were expected late today, but final, complete returns could take days if not weeks.

“Let us make tomorrow a national celebration, a day of national unity and victory over terrorism and those who oppose our democratic march,” President Talabani told a nationwide television audience.

Election of the new parliament, which will serve a four-year term, marks the final step in the American blueprint for democracy. The vote will cap a process that included the transfer of sovereignty last year, selection of an interim parliament January 30 and ratification of the constitution in October. The new parliament will name a government, including a new prime minister.

“In spite of the violence, Iraqis have met every milestone,” President Bush said in Washington.

“We are in Iraq today because our goal has always been more than the removal of a brutal dictator,” Mr. Bush said. “It is to leave a free and democratic Iraq in its place.”

A coalition of Shiite religious parties, which dominate the current administration, was expected to win the biggest number of parliament seats – but not enough to form a new government without alliances with rival groups.

But Washington hopes more Sunni Arabs will win seats and help establish a government that can lure other Sunnis away from the insurgency. Such a development would make it possible for America and its partners to begin to draw down their troops next year.

More than 1,000 Sunni clerics called on their followers to vote, and insurgent groups, including Al Qaeda in Iraq and the Islamic Army in Iraq, pledged not to attack polling stations even though they oppose the political process.