Emperor Naruhito is believed to be "concerned" that the Tokyo Olympics and Paralympics could cause a further increase in coronavirus cases, the head of the Imperial Household Agency said Thursday.

"His majesty is very worried about the current infection situation of the COVID-19 disease," Yasuhiko Nishimura, grand steward of the agency, said at a news conference.

"I suppose that (the emperor) is concerned that while there are voices of anxiety among the public, the holding (of the games) may lead to the expansion of infections," Nishimura said.