He said people might find roads blocked, and other unexpected security delays.
"We are taking these steps to keep communities and their officers safe. We would not do this if it was not absolutely necessary to protect life," Finlay said.
Several spectators said they doubted that any IRA splinter group would seriously disrupt the torch run. They said even if Irish republican extremists tried something, Northern Ireland's people were determined to keep partying anyway.
"We're not going to let that crowd of morons ruin our day. They represent zero-point-zero of the population. This is the real Northern Ireland," said Gareth Wilson, 35, standing with his wife and two sons by the roadside with cell phones in hand, each snapping pictures as the torch cavalcade passed.
Olympic torch relay May 19-July 27, http://l2012.cm/Juynr7
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