The primary was to select candidates for mayor and other city offices.

Naomi Bernstein, a spokeswoman for the Board of Elections, said the judge charged with overseeing the election called it off because of the massive confusion and terror that followed the attack on the twin towers, which both collapsed.

There was no immediate word on when the election would take place.

Four Democrats and two Republicans are in the running for their parties' nod Tuesday to run in the November election and succeed Mayor Rudolph Giuliani. The Republican mayor is barred by a term-limits law from running again.