BURLINGTON, Vt. (AP) _ A federal grand jury has indicted three Lebanese-born Canadians for trying to smuggle a bomb into the United States, authorities said.

The three men, Walid Nicolas Kabbani, 30, Walid Majiv Mourad, 39, and Georges Fouad Nicolas Younan, 44, were arrested in the early hours of Oct. 24, a short time after they crossed the border at Richford.

Authorities have said the three, being held without bail, live in the Montreal area and are in the textile business.

Neither Thursday's indictment, nor prosecutors revealed any motive.

U.S. Attorney George Terwilliger III said the investigation was continuing but refused other comment.

Affidavits filed in the case give the following account:

Mourad and Younan crossed the border late on Oct. 23 in a van, telling immigration officials they were on their way to Boston for the weekend.

A short time later, Kabbani was spotted by Richford Police Chief Richard Jewett carrying a black bag and walking near railroad tracks that cross the border.

Jewett then spotted the van carrying Mourad and Younan parked illegally in Richford and asked them to move it.

After that, the chief saw Kabbani again, but without the bag. Kabbani told the chief he was returning to Canada from Burlington. Jewett offered him a ride to the border station, and Kabbani accepted.

Jewett then returned to where he had met Kabbani, searched with a flashlight, found the bag and took it to the border station.

He and Border Patrol agents opened the bag and found two metal cylinders taped together with wooden plugs placed in a small opening in the top of each tube, and a third metal cylinder with wires attached.

The FBI and a state police bomb expert determined it was an explosive device.

Kabbani was placed under arrest, while Mourad and Younan were arrested the next morning as they left a motel.

The indictment charges the three with unlawfully transporting a bomb in interstate and foreign commerce, possessing a destructive device not registered to them, and possessing a destructive device that had been imported into the United States.

It also charges Mourad and Younan with conspiring to move Kabbani into the country illegally, and Kabbani with entering the country illegally.

Convictions on the first three counts carry maximum penalties of 10 years in prison. The fourth carries a maximum five-year term, and the fifth a six- month term.

The grand jury action precluded the need for a probable cause hearing that had been scheduled for Thursday in U.S. District Court.