TOKYO - The parents of Princess Mako, the eldest granddaughter of Emperor Akihito, demanded her boyfriend Kei Komuro and his mother solve a financial problem before the imperial agency postponed in February ceremonies for their formal engagement and marriage, a source close to the matter said Wednesday.

• Japan's Princess Mako to postpone wedding due to 'lack of preparation'

Prince Akishino and his wife Princess Kiko told the Komuros from late last year to early this year that a ceremony for their official engagement, which had been scheduled in March, could not be held without resolving his family's financial trouble, reported by weekly magazines.

In September, the couple, both 26 years old, announced their engagement after receiving the emperor's blessing. But the Imperial Household Agency announced in February the postponement, citing a "lack of preparation."

The abrupt postponement followed weekly magazine reports of a financial dispute between Komuro's mother and her former fiance over her son's educational expenses, which were shouldered by the mother's former partner.

The princess' family was not notified beforehand of what was reported as a "debt problem," the source said.

The Komuro family has told the princess' parents that they did not regard the money as a "debt" and are seeking to hold talks with the mother's former fiance, according to the source.

Prince Akishino and Princess Kiko have also asked the Komuros to explain the matter publicly but so far no action has been taken, the source added.

A series of court rituals, including the betrothal ceremony of "Nosai no Gi" that precedes the official wedding -- which was originally planned for November -- were postponed until 2020.

Despite the postponement of their nuptial, Princess Mako and Komuro are staying in close contact with each other and their intention to marry is unchanged, according to the source.

Komuro, a former classmate of Princess Mako from university days, left Japan on Tuesday to study in New York for three years with the aim of passing the U.S. state's bar examination.

==Kyodo