Major Olympic sponsors will not attend this week's opening ceremony in Tokyo, domestic media said on Tuesday, dealing another blow to a slimmed-down Games as more athletes tested positive for the coronavirus.

The Games, postponed last year because of the pandemic, open on Friday but will be held without spectators after Japan this month decided that participants would compete in empty venues to minimise the risk of further infections as cases in Tokyo rise.

Officials from top Olympic sponsor Panasonic Corp, as well as Fujitsu Ltd and NEC Corp, will skip the event, several local media outlets said, after...