"China and North Korea have normal country relations. At the same time we also oppose North Korea's conducting of nuclear tests. China calls on the relevant parties to be calm and exercise restraint, and avoid taking any further action that would cause further escalation," said Hua Chunying of the Chinese foreign ministry at a press conference Friday.
The North Korean government angrily denounced a U.N. resolution, drawn by China and the United States and passed Thursday, placing additional sanctions on North Korean banking and imports, the BBC reported Friday.
In response, the North Korean government pulled out of all non-aggression pacts with South Korea, cut off the North-South telephone hotline, closed the Panmunjon border crossing and pulled out of the armistice that ended the war between the two sides, the North Korean news agency KCNA said.
South Korean President Park Geun-hye called the situation "very grave," saying she would "deal strongly" with provocation from North Korea, the BBC said.
She said she was prepared to talk with Pyongyang leaders if they are "on the path toward change."
"It is regrettable that the North has unilaterally annulled past non-aggression and denuclearization agreements and moved to escalate tensions," said Kim Hyung-suk, South Korea's Unification Ministry spokesman. "Pyongyang must realize that making threats will not allow them to win anything."
U.S. officials said "extreme rhetoric" from North Korea wasn't unusual and the United States could protect itself and its allies from any attack.