Foreign firms are evacuating staff in Japan, after fears of radiation leaks at the Fukushima Daiichi plant escalated further.
German car maker BMW and car part maker Continental were among companies moving employees out of the country.
Others, including software group SAP and chipmaker Infineon are transporting staff to southern cities within Japan.
Workers have suspended operations at the nuclear plant after a rise in radiation levels.
Radiation levels in Tokyo were higher than normal, officials said, but not at levels dangerous to humans.
"We've offered to move staff to the South but only a small amount have decided to go," said a spokesperson for Infineon.
SAP said it will evacuate offices in Tokyo, Osaka and Nagoya.
It said it has offered about 1100 employees and their families transport and hotel rooms further south.
Private equity firm Blackstone is closing its office in Tokyo and relocating staff as well, according to the Bloomberg news agency.
Companies are moving to ensure the safety of their staff after an explosion and fire broke out yesterday at the Fukushima Daiichi power plant, about 220km north of the capital.
However, some financial firms in Japan are operating "business as usual", the International Bankers Association in Japan said in a statement.
There is so much confusion about what is going on at theIt represents companies including Goldman Sachs, JP Morgan and Barclays.