Tokyo Olympic organisers grappled with the cancellation of test events for several pool sports just days after they were restarted, as the Covid-19 pandemic continued to disrupt preparations for the start of the Summer Games in July.
The International Swimming Federation (Fina) has cancelled Olympic qualifiers for diving and artistic swimming that were to double as test events this month and next, the calendar on its website shows.
Separately, organisers said on Tuesday they had decided to postpone a water polo test event planned for this weekend.
Organisers are seeking a suitable date in May or June to hold the event, the Tokyo 2020 committee saidt.
"Carrying out test events is greatly important for the preparation of the Tokyo 2020 Games," Tokyo 2020 said.
"In order to ensure the best level of preparations for these test events and for the Tokyo 2020 Games, considering the schedule of each stakeholder under the current global Covid-19 conditions, it was felt that postponing the events was necessary."
Public broadcaster NHK reported earlier that overseas officials were unable to come to Japan for the event due to strict Covid-19 countermeasures. A Tokyo 2020 spokeswoman declined to comment.
The news is a blow for organisers just days after they restarted test events, which are an important dry run to confirm the Games' operational capabilities, for the first time in more than a year.
It also highlights the mammoth task of planning for the world's biggest sporting event at a time when Japan is struggling to combat a fourth wave of Covid-19 infections that has begun to gather.
Japan's vaccination campaign made a slow start and some prefectures were battling a resurgence in new infections, with one hot spot, the city of Osaka, expected to cancel its leg of the torch relay next week.
Organisers were initially planning 18 test events in April and May, starting with wheelchair rugby April 3-4.
But Fina has cancelled its Olympic qualifiers in Tokyo, which were also to be test events, for diving scheduled for April 18-23 and artistic swimming May 1-4, according to its website.
Fina has also cancelled a non-test event, the Olympic marathon swim qualifier in the southern Japanese city of Fukuoka in late May, its website shows.
Fina had said on Friday it was reviewing its qualifiers planned for Japan, without giving a reason, and that it would make an announcement this week. On Sunday, Yasuo Mori, a senior Tokyo 2020 official, said Fina intended to cancel the events and that organisers would hold talks with the swimming federation this week.
The BBC, citing a letter it had accessed from Fina to national federations, reported on Friday the diving event was cancelled because the organisers' planned Covid-19 precautions "will not properly ensure" the safety of athletes.
The BBC report also said Fina was unhappy that several Japanese embassies around the world had yet to issue visas to nations that planned to compete, and cited other factors including rising costs of measures to control the spread of Covid-19 that the global body was asked to pay for.