At least eight pedestrians, including some Mexican World Cup fans, were injured after a taxi mounted a crowded pavement in central Moscow.
CCTV footage posted on social media showed the car veer out of a queue of stationary traffic and accelerate into pedestrians before coming to a halt.
The driver then fled, pursued by several passers-by.
Moscow police said the driver was a 28-year-old national of Kyrgyzstan, who was now being questioned in custody.
The city's mayor said the driver lost control of the car, while Russia's Interfax news agency quoted an unnamed source as saying he had fallen asleep at the wheel.
But one witness, who was across the road at the time of the crash, said it did not appear to be accidental.
"I have the feeling that he did it deliberately because he was in the traffic jam with the cars going really slowly," said Viktoria Geranovich, "How could he lose control of the wheel, push the gas and drive into the crowds?"
She said "mostly girls" were knocked down, but people rushed to help and the ambulance arrived quickly. "Thank god everything went well. It's scary that this happened in the very centre."
An unidentified official said of the injured: "Seven of them are in a satisfactory condition and one woman is in a moderate condition."
Image copyrightREUTERSThe incident happened not far from the Kremlin and Red Square, an area packed with tourists.
Russia is currently hosting the World Cup, and promised "unprecedented" security measures in all cities hosting the games.