Police said they had been called to reports of an explosion and people running at Southgate station at 7.03 pm (1803 GMT).
They closed the station and said officers were dealing with a suspicious package.
“Enquires are ongoing to establish the cause of a reported minor explosion,” the Metropolitan Police said on Twitter. “We are not aware of any serious injury.”
Local residents reported on Twitter they were escorted out of their homes and others were instructed to stay in restaurants and shops near the scene.
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