Police sent a group of biochemical crime experts on Wednesday to investigate a suspicious letter delivered to the U-S Consulate in Osaka, officials said.
The envelope, with the address written in Japanese and mailed inside the country, apparently contained powder inside it, said an Osaka Prefectural (state) Police investigator on condition of
A spokesman of the U-S Consulate General for Osaka-Kobe said officials were waiting for police to identify the letter's contents, a fine white powder which fell out of the envelope when a consulate employee shook it.
Meanwhile in a separate incident, local media reported that an item of mail addressed to Prime Minister Junichiro Koizumi arrived at his official Tokyo residence on Wednesday.
The letter also contained white powder, which police later revealed to be starch, television stations claimed.
Similar mails arrived at Self Defence Force (Japanese military) headquarters and several newspaper companies, according to media reports.
Japanese postal authorities this week have tightened checks on mail and parcels arriving from abroad in an effort to prevent bioterrorism.