Preoccupied with the attack on the World Trade Center, few New Yorkers turned out for the mayoral primary Tuesday, an election that has been thrown into confusion by the strong hints that Mayor Rudolph Giuliani might try to extend his stay in office.

Early returns indicated that Bronx Borough President Fernando Ferrer would face Public Advocate Mark Green in an Oct. 11 runoff election for the Democratic nomination.

On the Republican side, billionaire business-news entrepreneur Michael Bloomberg ran away with the nomination, trouncing former U.S. Rep. Herman Badillo. Bloomberg spent $20 million on his campaign, much of it on television advertising. With a quarter of the ballots counted, Bloomberg had received 66 percent of the vote.

Of the four Democratic primary candidates, Ferrer had 36 percent of the votes and Green had 32 percent, with a quarter of the votes counted. City Council Speaker Peter Vallone and Comptroller Alan Hevesi were trailing.

Under New York election law, a runoff is required when no candidate receives at least 40 percent of the vote.

The primary originally was scheduled for Sept. 11, the day of the World Trade Center attacks. Voting had already begun when two hijacked passenger jets crashed into the twin towers.

City officials quickly postponed the primary. Citizens who had already voted were told they should vote again Tuesday, except for those who had cast absentee ballots, which had not been counted before the attacks.

The attack also pushed back the date of the runoff, initially scheduled for Tuesday, to Oct. 11. The general election is scheduled for Nov. 6.

Exit polls Tuesday indicated Green would defeat Ferrer in a runoff.

Tuesday's turnout was projected to amount to no more than 30 percent, one of the lowest turnouts in a city election. For those who voted, taking part in the election was a way of affirming a basic American right in the face of the attacks.

"It's important to show the people who did this thing two weeks ago that they can't stop us from voting," said Les Jacobowitz at a poll near City Hall.

Jacobowitz was among thousands of New Yorkers who live near the World Trade Center and had to vote at relocated polling places. Seven polling places near the devastated site remained off limits as the removal of debris and the search for victims continues. The temporary balloting spots included a tent on a street corner.

Exit polls also indicated that about 15 percent of the vote went to write-in candidates, but it was not known for whom those voters cast their ballots. Last week New York Gov. George Pataki said that if he were a city resident, he would write in Giuliani's name.

Giuliani, whose approval rating has shot up to 91 percent since the attack, is prohibited from running because of the city's term limits statute.

New Yorkers seem to have a somewhat contradictory view of having Giuliani involved in directing the city's recovery beyond the end of his term on Dec. 31. A Marist College poll of 508 city residents released Tuesday found 55 percent think Giuliani should find a way to remain in office, but 52 percent don't want to eliminate term limits.

The Marist poll results suggest support for some emergency measure that would extend Giuliani's term for six months to a year. Revoking the term limits statute or passing a one-time term extension would require support from either the state Assembly or the City Council, both controlled by Democrats. And after eight years of a Republican mayor, Democrats are eager to win back the mayor's office.

In the days leading up to Tuesday's primary, Giuliani sent mixed signals about his desire to stay in office. As part of his campaign to revive the normal rhythms of city life, he urged New Yorkers to vote. He also told them not to write in his name. But he has clearly considered the political and legal hurdles that would have to be cleared to extend his term.

"It can be done," Giuliani said during a Monday appearance on "The Late Show with David Letterman." He added: "It's really a question of whether it should be done. I have to really think about that."