U.S. President Barack Obama has called the North Korean nuclear issue a common challenge that requires joint efforts by the U.S. and China.

Obama’s remark came at the start of talks with Chinese President Xi Jinping on Friday at the Sunnylands estate in Palm Springs, California.

The U.S. president said Washington and Beijing are going to have a healthy economic competition but also have many challenges to cooperate on ranging from “North Korea's nuclear and missile programs -- to proliferation, to issues like climate change.”

He added that his country welcomes the continuing peaceful rise of China as a world power, saying that a peaceful and stable and prosperous China is good for the world.

The visiting Chinese president said on his part that the China-U.S. relationship has gone through winds and rains and it came to a historical starting point. He also stressed China and the U.S. should now find ways to join together and promote peace and development in the world.

During the first session of their two-day summit, they discussed exploring avenues to expand partnerships on multiple global issues. Officials said the three-hour session was focused on the security issues, including North Korea’s nuclear threat, which Washington aims to foster cooperation with Beijing.

However, with Seoul and Pyongyang facing a turning point in inter-Korean relations, neither Obama nor Xi elaborated to reporters on their exact stances on North Korea.

Experts say the precise direction of their North Korea policies will only surface when South and North Korea hold talks and when President Park Geun-hye meets with Xi Jinping later this month in Beijing.