SEOUL, March 6 (UPI) -- South Korean officials, voicing outrage Friday, demanded North Korea pull its warning of flight safety in its airspace, calling the statement "inhumane."
The already tense relations between the two countries became more strained Thursday after North Korea said it is "compelled to declare that security cannot be guaranteed for South Korean civil airplanes" flying in its airspace, South Korean news agency Yonhap reported.
"To militarily threaten the normal operations of civil airplanes not only violates international rules but is also an inhumane act that can never be justified," said South Korea's Unification Ministry spokesman Kim Ho-nyoun.
North Korea said a joint South Korea-U.S. military exercise was to blame for its actions and that drill could lead to an actual war.
In Washington, a U.S. State Department spokesman called the threat "distinctly unhelpful."
The warning prompted South Korean airlines to reroute flights but since U.S. and other international carriers weren't mentioned in the North Korean warning, they likely would be unaffected, said the South Korean ministry spokesman said.
Officials said South Korean commercial ships will avoid areas near North Korean waters in the East Sea, traveling through Japanese waters instead.
North Korea had demanded the annual drill, scheduled to start Monday, be canceled earlier during a meeting with the U.S.-led U.N. Command, Yonhap said.
