NEW YORK (AP) – A bomb scare emptied Pennsylvania Station and disrupted service on Amtrak, commuter trains and city subways for about an hour on Sunday.

The busy commuter hub was evacuated after someone threw a backpack at an Amtrak agent and said it was a bomb, said Marissa Baldeo, a spokeswoman for New York City Transit. The threat was a false alarm, and service on all lines was restored at about 1:25 p.m.

Sarah Swain, an Amtrak spokeswoman, said service was suspended because of police activity and declined to discuss details. She said Amtrak police had detained a man but said she did not know whether he had been arrested.

The incident came days after a second bombing attack in London, which prompted New York police to start random inspections of subway riders’ bags.

But travelers seemed to be taking the disruption in stride.

Tim Allen, a Londoner headed from New York to Boston, said Penn Station was emptied at about 12:15. He has endured similar false alarms recently in London.

“This is the second time this has happened in two and a half weeks to me,” he said.

After evacuating Penn Station, police sealed the Eighth Avenue entrance with yellow tape and moved everyone across the avenue to the west side.

The incident was over as quickly as it began. One minute, camouflage-clad soldiers were shouting, “Penn Station is closed indefinitely,” and the next minute they got the all clear and started letting people into the station.

The service disruption affected Amtrak, the Long Island Rail Road, New Jersey Transit and the Seventh and Eighth Avenue subway lines.

Also Sunday, a double-decker Gray Line tourist bus was evacuated in midtown Manhattan after a bus company supervisor told police that five male passengers with “stuffed” pockets had raised her suspicions. Police handcuffed five men and searched about 60 passengers before determining there was no threat.

In London on Sunday, Metropolitan Police Commissioner Sir Ian Blair said there were similarities between the explosives used in Thursday’s failed bomb attacks and those detonated July 7 that killed 56. But he said investigators still had no proof the two strikes were linked.

New York City Mayor Michael Bloomberg announced Thursday following the latest attacks in London that police would begin conducting random searches of packages and backpacks carried by people entering the subways.