The Reconstruction Agency is considering punishment for its senior bureaucrat responsible for providing support to people affected by the Fukushima nuclear disaster, for allegedly posting disparaging tweets targeted at specific Diet lawmakers and civic groups, agency officials said Thursday, the same day the bad-mouthing came to light.

Yasuhisa Mizuno, 45, is now under investigation by the agency over the Twitter messages.

"I went to a meeting to listen to those sh**head leftists heaping scorn," Mizuno allegedly tweeted after attending a meeting in March in Tokyo organized by a civic group supporting Fukushima disaster victims. He represented the agency at the meeting.