Some 1,500 people were evacuated from the station, located on Line B in the north-east of Rome, as emergency services rushed to the scene.
The panic started when a train packed with commuters came to a sudden stop and passengers witnessed smoke and sparks – believed to be the result of a fault in an overhead cable – prompting several to call the authorities to report an explosion.
"I heard two explosions, I thought it was an attack," one man told Ansa news agency outside the station.
"The train suddenly stopped in the tunnel around 8.20 and people started to panic," another passenger said, while one witness complained that passengers had remained stuck in the dark for 20 minutes before they were instructed to get off the train and walk down the tracks to the nearest platform.
Three people were treated for panic attacks, according to police, who said that no other injuries were reported.
Rome's public transport authority, Atac, reported a "technical fault on the line" and said that service was partially suspended, to be replaced by buses.
By mid-morning Line B remained suspended between the stations either side of Policlinino, Castro Pretorio and Monti Tiburtini – adding to the woes of the capital's travellers, who were already feeling the effects of a four-hour public transport strike.
The strike, which severely reduced service on the metro, buses, trams and some overground trains between 8.30 am and 12.30 pm, was called to protest what unions say are unsafe conditions for workers and passengers on Rome's strained public transport network.
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Photo: Tiziana Fabi/AFP