Two toddlers, a boy and a girl aged two and three, plunged four storeys to their deaths in a mall in the Chinese city of Tianjin on Monday (Feb 27) night.

Local media reports said one of the children's parents, who was holding them while standing near a balcony on the fourth floor of Joy City Shopping Mall, had lost the grip on one of the children.

The second child fell from the other arm as the parent was trying to reach out to grab the first one. Both died instantly after landing on the mall's ground floor.

It was not clear if the mother or father had been holding on to the children.

There was a 1.3m-high glass barrier at the balcony, according to news website Sina.

Video footage of the children's parents, wailing in grief as they kneel next to their dead children, has been circulated widely on social media.

Police investigations are reportedly ongoing.

The tragedy mirrors a similar incident in November last year, when a grandmother lost her balance while getting on a downward escalator on the third floor of a shopping mall in Shanghai.

The four-month-old baby she was carrying fell off the side of the escalator and died.