BEIJING: China and the United States stressed the positives in their complex relationship on Friday during meetings between US National Security Adviser Susan Rice and Chinese officials ahead of a US visit by Chinese President Xi Jinping next month.

While the world's two largest economies have important mutual interests, like trying to rein in North Korea's nuclear program, deep disagreements exist over everything from Internet security to China's claims in the South China Sea.

"We have seen our bilateral relationship evolve and strengthen in recent months. And we have found areas of broadened and deepened cooperation that we are certainly looking forward to building upon," Rice told China's top diplomat, State Councillor Yang Jiechi, who outranks the foreign minister.

"At the same time, we have been able to discuss frankly our differences, which we both acknowledge need to be addressed effectively."

Yang said that both countries had cooperated closely over the Iran and North Korean nuclear issues.

"With shared efforts on both sides, China-US relations have maintained a trend of overall positive development recently," he added.

Rice also met Fan Changlong, one of the vice chairmen of the Central Military Commission, which Xi heads and which controls the Chinese armed forces, the world's largest.

Fan said that his meeting with Rice was the fourth in one year, which showed the importance the two countries attach to military-to-military relations.

Rice said the United States was committed to developing healthy and stable ties with the People's Liberation Army, and praised cooperation between the two over the Ebola outbreak in West Africa and efforts to fight piracy in the Gulf of Aden.

There was no mention in any of the comments in front of reporters of cyber issues or the South China Sea.

The United States has repeatedly expressed concern about Chinese reclamation work in the South China Sea. China says the United States is not a claimant nation in the dispute and should stay out of it.

China claims most of the South China Sea, through which $5 trillion in ship-borne trade passes every year, and rejects the rival claims of Vietnam, the Philippines, Brunei, Malaysia and Taiwan.