A support group for a one-year-old Japanese girl who needs a heart transplant says it has raised enough money for her to have the operation in the United States.

Sato Aoi from Tokyo developed serious heart failure after undergoing surgeries to close holes in her heart wall.

Last month, her parents and supporters launched an appeal for donations so that Aoi can receive a transplant at a US hospital.

On Monday, the support group said the target amount of 530 million yen, or about 3.9 million dollars, had been raised.

High medical fees in the US and the weaker Japanese currency have pushed up the estimated cost. Aoi will need to use a chartered aircraft as she has an auxiliary artificial heart.

The group says preparations will be made for Aoi to travel to the US next month or later.

Aoi's parents expressed gratitude for people's kindness and enthusiasm, and said they could reach the starting line to keep her alive.

There have only been 31 organ transplants in Japan from donors aged 10 or below in the 10 years through 2021. The number of donors decreased during the pandemic. As of the end of October, 44 patients under the age of 10 were waiting for heart transplants.