Television and radio broadcasting cables at two unmanned relay stations in Isobe, Mie Prefecture, were cut late Saturday, disrupting broadcasts by NHK and local private broadcasters in the southern part of the prefecture, local police said Sunday.
The disruptions were corrected by early Sunday, but police have launched an investigation. They believe someone cut the cables with a knife-like object.
Four cables at NHK's relay station were also cut on Thursday, leading to similar broadcast disruptions in the same area, they said.
According to police, the sites affected in the latest incident were the NHK Isobe Television Relay Station -- used by the public broadcaster, Chukyo TV Broadcasting Co. and FM Mie -- and another relay station used by four local broadcasters. Five cables were cut at the NHK relay station, while six were severed at the other location, police said.
The two relay stations are both one-story structures of steel-reinforced concrete. The cables were 2 cm in diameter and were wrapped around antennas on the roofs of the stations.
Police said the NHK relay station is surrounded by a 2-meter-high iron fence, but that the lock on the entrance gate was broken.
As a result of the severed cables, TV and radio broadcasts were temporarily stopped in at least eight municipalities in the prefecture. NHK officials said that some 6,100 households had television broadcasts disrupted, and roughly 52,000 households could not receive radio broadcasts.
Kiyonobu Mizutani, deputy bureau chief of NHK's Tsu bureau, apologized to viewers.
"We will leave the investigation in the hands of police, and will consider measures to beef up security at the relay station, such as setting up security cameras," he said.