PARIS - A burst of unexplained noises have scared some travelers at the Gare du Nord train station in Paris, where citizens are on edge after last week's attacks that killed 130 people.

However, Stephane Brossard of the Paris police told the AP that the Sunday afternoon noises that some interpreted as gunshots were caused by a pigeon that got electrocuted on the train tracks.

In a sign of the nervousness that has swept through Paris since the attacks, witnesses went to social media to describe how passengers ran out of their trains after hearing the noises.

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The status of the pigeon was not immediately known.

This is at least the second time since the deadly attacks a "collective panic" has swept through crowds in Paris.

During a memorial for victims in the city's iconic Plaza de Republique shortly after the attacks, someone apparently tossed firecrackers into a crowd, sending fearful residents running in all directions.

At least one and likely more of the terrorists with direct involvement in the Paris attacks are still on the loose, causing officials in Brussels to effectively shut the city down to the threat of further attacks.