North Korea was not responding to daily contact via an inter-Korean liaison line Friday, South Korea's unification ministry said.
"There was no opening call via the liaison line at 9 a.m.," the ministry said in a message to reporters.
The government said as there was no problem in communication lines in the South, it will closely monitor the situation, including the possibility of a technical problem in the North.
The two Koreas hold phone calls twice a day via their joint liaison office channel
Source: Yonhap News Agency