said it and several affiliated organizations, including a pro-Pyongyang Korean school in Tokyo, had received harassing phone calls after the missile launches. The group said no one had been physically threatened.
The Metropolitan Police Department, responding to a request from the National Police Agency, increased the number of officers on guard at Chongryun's head office in central Tokyo and several other facilities, in case rightwing groups decide to demonstrate.
The metro police have told their stations to be on the lookout for harassment of students attending Korean schools run by Pyongyang supporters.
Many of those schools have asked their students' parents to patrol nearby train stations and along roads leading to the schools, a Chongryun official said.
In addition, some parents have asked teachers to cancel after-school activities and let the children go home early, the official said.
Police in Tokyo also have beefed up security at key government buildings, including the Prime Minister's Official Residence and the Foreign Ministry, they said.
The increased security is in response to North Korea test-firing seven missiles, including a long-range Taepodong-2, earlier in the day. All landed in the Sea of Japan.
The Japanese government Wednesday banned the ferry Mangyongbong-92 from the nation's ports for six months, effective immediately, and barred North Korean officials, ship crews, and thus ships, and charter flights from entering Japan.
The sanctions will force some Korean schools to cancel trips to North Korea later this year, the official said.
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