PHILADELPHIA (AP) _ Residents across the nation sipped coffee on their porches, marched in parades and shined flashlights into crime-ridden corners of their neighborhoods for the anti-crime event National Night Out.

Some 25 million people in 8,400 communities were expected to turn on their porch lights and spend Tuesday night outside, said organizer Matt Peskin.

''What seems to be happening is people are meeting neighbors on their street that they never knew before,'' he said. ''That's the foundation for crime prevention.''

Peskin is director of the National Association of Town Watch in suburban Wynnewood, which came up with the idea for the annual event nine years ago.

At a ceremony in Washington, FBI Director William S. Sessions flipped a switch turning on a watermelon-sized light bulb symbolic of the event. ''The key is citizen involvement, to care enough to be involved,'' he said.

In Miami, police and community leaders led a caravan of 50 cars through many of the city's most crime-ridden neighborhoods.

In Camden, N.J., 125 people held a prayer vigil near the house of an anti- drug activist that was firebombed last week.

More than 150 people in the Germantown section of Philadelphia took a flashlight walk through their neighborhood, which in recent years has seen a rise in burglaries, drug dealing and car thefts.

In Northeast Philadelphia, a group held a parade, followed by a party for 200 people at a recreation center.

In other sections of the city, people sat on their stoops, drinking coffee and chatting with neighbors.

''We never see each other,'' said Salley Downey. ''This is just an excuse.''

In Vicksburg, Miss., police Sgt. Douglas Arp descended from a platform on a billboard, where he had spent the past week to call attention to the event.

''We went from nobody in Vicksburg knowing what National Night Out is to nearly everybody knowing what National Night Out is,'' Arp said.