Updated at 3:03 a.m. CST

DES MOINES – President Bush forged the narrowest of leads over Democratic nominee John Kerry early Wednesday on the strength of a strong showing in heavily Republican western Iowa.

It appears the most important state with an outcome still in question is Ohio. Its 20 electoral votes would almost certainly assure Bush his second term as president. Bush administration officials announced Wednesday morning that the president would declare victory in the election soon.

With 98 percent of Iowa’s precincts reporting, Bush led Kerry by 11,618 votes, but a series of issues raised doubt about the outcome.

State election officials said 30,000 to 50,000 absentee ballots had not been returned as of Election Day. Those ballots had to be postmarked by Monday, but county election officials have until noon next Monday to receive them.

In addition, there were 10,000 to 15,000 provisional ballots cast, and those will be reviewed Thursday. That’s consistent with the number cast in 2000.

Also Wednesday, CNN reported that broken machines in two counties and additional delays in opening absentee ballots will delay Iowa reporting its final count.

Election officials told CNN that optical scanners used to read ballots in Greene and Harrison counties had broken and that ballots would not be counted until Wednesday.

Before Tuesday, as the number of states truly up for grabs dwindled, both parties threw a massive number of television commercials at voters in Iowa, the main rivals visited the state every few days and the two sides built huge voter-turnout machines.

Telephone banks and canvassers touched millions of voters in a state where Democrats won by just 4,144 votes in 2000.

Bush and Kerry brought considerable political history in Iowa to the contest. Bush won the state’s leadoff precinct causes in 2000, a victory that helped launch him to the Republican nomination and eventually to the White House.

Kerry began campaigning in Iowa nearly three years ago and he spent much of last year struggling with a campaign that featured infighting and had trouble finding a theme.

His surprising win in the Jan. 19 Iowa caucuses gave him the momentum to claim the Democratic nomination. In some ways, Iowa party activists picked the ticket, because running mate John Edwards’ equally surprising second-place showing in Iowa allowed him to outlast all of his Democratic rivals but Kerry.

Edwards spent the closing days of the campaign courting Iowa voters. Not to give an inch, Vice President Dick Cheney did the same thing as both campaigns battled for Iowa’s seven electoral votes.

The last Republican to carry Iowa was Ronald Reagan in 1984.

— Daily staff reports contributed to this article.