BAGHDAD, 15 October 2005 — Iraqis hunkered down in their homes yesterday, with streets almost empty during the day and a blackout plunging much of Baghdad into darkness on the eve of a landmark vote on a draft constitution supported by a Shiite-Kurdish majority but which has split Sunni Arab ranks.

In Friday sermons across the nation, the message from Shiite pulpits was an unequivocal “yes,” but it was not so clear-cut in Sunni Arab mosques — varying from “yes” to “no” and “vote your conscience.” Kurds, a sizable minority that is mainly Sunni, fully support the charter.

Fearing violence, Iraqis stayed home yesterday and the capital’s usually congested streets were virtually deserted by late afternoon. Most shops did not open at all. Those that did closed early.

Tens of thousands of Iraqi Army troops and policemen threw security rings around the nation’s estimated 6,000 polling stations and set up checkpoints on highways and inside cities.

The blackout hit much of the greater Baghdad area shortly after nightfall. The cause of the outage was not immediately clear, although widespread power cuts in the past have been blamed on insurgent attacks. There was a similar power outage in the southern city of Basra and officials blamed it on saboteurs. Most of Iraq’s Shiites, about 60 percent of an estimated 26 million population, is expected to vote “yes” in the referendum. In an effort to familiarize voters with the draft, local TV stations aired readings of last-minute amendments reached this week, too late to be included in the text distributed to the voters.

Those amendments convinced the Iraqi Islamic Party, the country’s largest Sunni Arab political group, to drop its opposition to the draft and call on its supporters to vote “yes”. The move split Sunni Arab ranks and boosted the chances for the draft’s passage.

The party’s change of heart triggered instant retaliation by insurgents. They exploded a bomb just outside the party office in central Baghdad, then set fire to its main office in Fallujah, a town west of Baghdad where the party enjoys some support.

In Azamiyah, several hundred demonstrators carrying banners calling for a “no” vote and branding Islamic Party leader Mohsen Abdul-Hamid “a traitor” marched at the area’s Grand Imam mosque, Iraq’s main Sunni Arab religious center.

Before dawn, an unidentified assailant tossed a grenade at the house of the mosque’s imam, pro-Islamic Party Sheikh Muayad Al-Azami. No one was hurt in the explosion. The night before, his son was threatened by opponents during prayers, Azami said.