chattr +a -V

Several news sites have substantially the same brief article (for example North Korea Cuts Phone Lines To Outside World and Nth Korea censoring phone lines: claim), referring to a Yonhap news service article which so far I havent been able to locate in English.

There's one tidbit in the latest which is interesting:

Since April, even people with permits to make international calls can only do so under the strict surveillance of security officials, [the Yonhap article] said.

Previous blog entry here at North Korea: near elimination of telephone communication. I haven't seen anything yet on this at One Free Korea or North Korea Zone.