OSAKA -- The Osaka Regional Taxation Bureau discharged an official Friday for allegedly leaking secret investigation information to a construction company president about four years ago.

The bureau also suspended another official for one month for allegedly obtaining the information illegally and passing it on to the dismissed official, bureau officials said. The names of both officials were withheld.

Osaka bureau spokesman Tadaaki Maruyama expressed "deep regret" and vowed to redouble efforts to prevent the further leaking of confidential information.

The dismissed official has persistently denied the allegations, as has the construction company president. But the bureau decided to take action after confirming the leak, the officials said.

The dismissed official received a copy of a document about a secret investigation into a construction company from his former colleague and then handed it to the company's president, the officials said.