The internal computer network of the state-run Japan Environmental Storage & Safety Corp., which manages temporary storage sites for decontaminated waste from the Fukushima nuclear disaster, has been infected by a computer virus, the Environment Ministry said Wednesday.

The operator also known as JESCO, an Environment Ministry affiliate, is investigating whether any information has been leaked, ministry officials said.

JESCO will run interim facilities to be set up on land in Fukushima Prefecture to store radioactive soil and other waste. Facility buildings have yet to be built amid slow progress in negotiations with landowners.

JESCO's computers do not store information on the landowners, which is kept at the Environment Ministry, the officials said.

JESCO shut down the network's external communications Tuesday night after a firm monitoring the network detected unintended data transmission, they said.

The Environment Ministry temporarily halted transportation of waste scheduled for earlier Wednesday, but the operation resumed later, the officials said.

The Japan Pension Service and the Tokyo chamber of commerce recently announced their respective computer networks had been hacked, causing data leaks of confidential information.