Foreign matter has been found in five unused vials of Pfizer Inc.'s COVID-19 vaccine in two cities near Tokyo and one in Osaka Prefecture, the local governments said Tuesday.

The vials containing the white floating matter belong to the same lot, FF5357, according to the cities of Sagamihara and Kamakura, both in Kanagawa Prefecture, and Sakai in western Japan.

A senior citizen receives the Pfizer coronavirus vaccine at a newly opened vaccination center in Kobe, western Japan, on May 25, 2021. (Kyodo) ==Kyodo

The three cities have requested Pfizer to analyze the substances.

The contaminants were discovered at three vaccination sites in Sagamihara between Saturday and Tuesday, one site in Kamakura on Sunday and one site in Sakai on Tuesday.

The cities said they did not use the doses containing the foreign matter while continuing to administer doses bearing the same lot number that were confirmed not contaminated.

Last month, the health ministry halted the use of around 1.63 million doses of Moderna Inc.'s COVID-19 vaccine as a precaution after foreign substances were discovered in numerous vials.

Related coverage:

Japan unable to link deaths to withdrawn batches of Moderna vaccine

Foreign matter in Moderna COVID vaccine identified as stainless metal