South Korean President Park Geun-hye conferred by phone with U.S. President Barack Obama about the North Korean nuclear standoff on Monday, her spokeswoman said, a day after the communist nation offered to hold high-level talks with Washington.

During the 20-minute talk, Obama briefed Park on the outcome of his summit with Chinese President Xi Jinping, saying he asked for Beijing's cooperation for North Korea's denuclearization as Pyongyang's nuclear and missile programs pose big threats to peace in Northeast Asia, presidential spokeswoman Kim Haing said.

Obama also told Park that Xi expressed China's commitment to a nuclear-free Korean Peninsula and promised not to recognize Pyongyang as a nuclear weapons state, while at the same time stressing the importance of resolving problems through dialogue, according to Kim.

Park and Obama agreed to continue to work closely on North Korea and other major issues, Kim said.

Kim declined to comment on whether they discussed Pyongyang's dialogue proposal.

On Sunday, the North proposed what it calls "senior-level" talks with the U.S., saying it wants to have broad and in-depth discussions on defusing military tensions, replacing the armistice system with a peace mechanism and other issues of mutual concern.

The U.S. said the North should first prove its seriousness about dialogue through actions. (Yonhap News)