KYIV, Oct 8 - Ukrainian police opened an investigation on Friday after a young lawmaker fell ill and died in a taxi in the capital Kyiv following what prosecutors said was a heart attack.

However, the head of Kyiv's police said it was most likely that Anton Poliakov, 33, had died of natural causes.

Poliakov belonged to the "For the Future" party, having defected from President Volodymyr Zelenskiy's ruling "Servant of the People" party over policy disagreements.