President Xi speaks during a bilateral meeting with US President Barack Obama during the Nuclear Security Summit in Washington on Thursday.

Obama said he and Xi are both committed to the denuclearization of the Korean Peninsula and the full implementation of the UN sanctions.

He praised the new steps the two countries announced on Thursday to accelerate implementation of the Paris Agreement.

In a joint statement on climate change, the two countries said they will both sign the Paris Agreement on April 22 and take necessary domestic steps to implement it as soon as possible.

"And I have been committed throughout my administration to working effectively with China on a whole range of issues and have developed a frank and effective level of communications cooperation with President Xi as we seek to expand cooperation between our countries and narrow our differences," Obama said.

He expressed concerns over issues including cybersecurity, human rights, maritime and intellectual property protection. He said he appreciated that Xi has held candid conversations in a constructive manner with him on these issues.

Obama also expressed wishes for a successful G20 summit in September in Hangzhou, East China's Zhejiang province.

In a press briefing afterward, China's Vice Foreign Minister Zheng Zeguang described the meeting as "positive, constructive and fruitful".

Ted Carpenter, senior fellow of defense and foreign policy at Cato Institute, said there needs to be serious discussions about developing some "rules of the road" in the South China Sea.

"Only preliminary steps can be taken now, but the current trend toward a dangerously confrontational stance by both countries can be halted and even reversed," he said.

Many in China regard the US as biased in handling the maritime territorial disputes between China and some of China's neighbors, including some US treaty allies.

Xi and Obama last met in Washington in September during Xi's state visit to the US, and then met Nov 30 in Paris at the climate conference. They also had three phone calls since then and are expected to meet at the G20 summit in China in September.

Zheng said both leaders said they are looking forward to meeting in Hangzhou.

China replaced Canada last year as the US' top trade partner. The two largest economies have greatly expanded their cooperation the last few years, such as in military-to-military exchanges, non-proliferation leading to the P5+1 Iran nuclear deal and in the training of young diplomats in Afghanistan.

anbaijie@chinadaily.com.cn