At least 31 municipalities have called off Tokyo Olympics and Paralympics "Host Town" programs to welcome overseas athletes for training camps and cultural exchanges before the games due to COVID-19 concerns, a government source said Wednesday.

Chiba Prefecture, east of Tokyo, said it was told on April 14 that the United States' athletics federation would not hold a pre-Olympic camp there out of concern for the safety of athletes.

Ono City in Fukui Prefecture in central Japan has also called off its Host Town program for East Timor's delegation. The government source said it has begun tracking the local governments that will not be participating as planned.

Chiba was planning to welcome around 120 members of the U.S. athletics team from early July and provide training facilities across three cities. However, details had been up in the air since the announcement of the one-year postponement of the Tokyo Games was made in March 2020.

The British wheelchair basketball team and Russia's fencing team will also not be training in the prefecture as planned.

The government is looking to cover host towns' expenses for COVID-19 countermeasures and has prepared guidelines. But smaller municipalities have had trouble securing the staff needed for the additional work, while an increasing number of overseas teams have been withdrawing on their own.

As of the end of April, a total of 528 municipalities had registered to welcome athletes from 184 countries and regions in a first-of-its-kind program for the Olympics and Paralympics. The government is calling for those communities' interactions to continue online and through other means.