Public health officials in Japan say they have imported potentially lethal viruses to develop ways to step up measures against infectious diseases ahead of next year's Tokyo Olympics and Paralympics.
The National Institute of Infectious Diseases says strains of five deadly viruses arrived at its branch office in Musashimurayama City to be used for tests.
They are the Ebola, South American, Lassa, Crimean-Congo and Marburg viruses.
Officials say the viruses will be kept in a laboratory with the highest biosafety level of 4, which means it is capable of handling the most dangerous pathogens.
Entry into the lab requires passage through double doors. The air pressure in the lab is kept lower than that of the adjacent room to prevent the viruses from escaping.
The institute also says security cameras are installed to monitor the people coming in and out of the lab.
Many city residents were against having the viruses brought in, but the mayor agreed on condition that strict safety measures would be introduced.
The institute says it will hold a briefing to residents and start preparations for tests to improve the quality of diagnoses using the viruses.