Atilla Aydiner, the mayor of Istanbul’s Bayrampasa district, told the media police believe a pipe bomb exploded near a metro station during rush hour Tuesday. Footage of the explosion has begun circulating through social media.

The explosion injured at least five people.

Reports emerged of a death, but Aydiner said they were not true.

NBC News reported “that evidence of a small hand-made bomb had been found outside the entrance of the metro station.” Other reports indicate the explosion shut down the subway. Ambulances and emergency personnel immediately rushed to the scene. As of publication, no one has taken responsibility for the bomb.