Chinese President Xi Jinping and US President Barack Obama's key national security aide hinted at tensions that divide their countries on Friday ahead of a state visit to Washington by Xi.

Meeting in Beijing with US national security adviser Susan Rice, Xi said that he looks forward to continuing a dialogue with Obama next month and working to ensure that China-US relations keep expanding.

"China attaches great importance to the growth of the China-US relationship," Xi said.

"We stand ready to further promote our practical cooperation, effectively manage the sensitive issues between us and strengthen the friendship between the people of both countries."

Rice responded that Xi's visit to the US will provide a "great opportunity" for the two countries "to strengthen and deepen our relationship" as they seek ways to benefit their peoples as well as the world.

"At the same time, we obviously have issues of difference and some difficulty that we need to work through and we will continue to do so," she said.

Xi's visit to the US comes as the countries have shown a willingness to cooperate on global matters ranging securing a nuclear deal with Iran to climate change.

But they have also clashed over issues including what Washington and some regional countries see as China's increasing assertiveness in Asia as well as its territorial disputes with countries close to the US such as the Philippines and Japan.

The tone of Rice's talks with other Chinese officials earlier Friday was similar to her encounter with Xi, highlighting areas of cooperation while recognising differences.

Rice told state councillor Yang Jiechi, China's top foreign policy official of the latter that both sides "acknowledge their need to be addressed effectively".

Yang said China and the US will stay in close communication on subjects including "the Iran and North Korean nuclear issues" and climate change, along with questions of "regional rights and interests".

That could refer to the South China Sea and East China Sea, where Beijing is embroiled in territorial disputes with its Southeast Asian neighbours and US treaty ally Japan respectively.

- 'Building a healthy relationship' -

The US and China, both permanent members of the United Nations Security Council, participated in negotiations that secured a landmark nuclear deal with Iran last month.

Beijing and Washington have also worked together as members of the six-party talks on North Korea's nuclear programme, which also take in Tokyo, Seoul, Moscow and Pyongyang.

That forum has been essentially dormant for years though China, which serves as host, supports its revival.

Rice also met with Fan Changlong, a vice chairman of the Communist Party's powerful Central Military Commission, which is chaired by Xi.

The US envoy said Washington was "deeply committed to building a healthy, stable, reliable military-to-military relationship with China" and stressed an agreement last year to "reduce the risk of unintended consequences" in encounters.

China claims virtually the entire South China Sea and has recently carried out major land reclamation in the area that analysts say will extend its military reach with the construction of bases and runways.

Beijing says the efforts have no aggressive intent and are meant to largely foster maritime safety in the waters, a major global trade artery which Washington says it is committed to keeping open to unhindered navigation.

Rice's visit comes as China prepares to hold a massive military parade next week to commemorate victory over Japan in World War II, though the US, as well as major Western countries, will not be sending top officials to participate.

Republican candidate Rubio rips into China's Xi
Washington (AFP) Aug 28, 2015 - Republican presidential hopeful Marco Rubio on Friday accused Xi Jinping of seeking to undermine US interests, in a notably personal attack ahead of the Chinese president's visit to Washington.

Rubio -- a Florida lawmaker who sits on the Senate foreign relations committee -- singled out the Chinese leader, as he branded Beijing's record on human rights a "disgrace."

China has been a frequent target for Republicans on the campaign trail, particularly following the global stock sell-off that many say was triggered by Beijing revaluing its currency.

Another Republican contender for the White House in the 2016 race, Wisconsin Governor Scott Walker, has called on President Barack Obama to cancel a planned state dinner with Xi.

But Rubio's tone was markedly personal.

While stating "China presents both opportunities and challenges for our people," he went on to lay blame for tensions at the communist boss's door.

"Xi Jinping is trying to convince his country's 1.3 billion people that the way to re-establish Chinese greatness is to undermine the United States and enhance China's influence at our expense," Rubio said.

"Under Xi Jinping's rule, China has intensified its campaign to push America out of Asia," he alleged.

"China aims to make it so costly and difficult for America to get involved in the region that we won't bother. In short, China is doing everything it can to make the 21st century a Chinese Century."

If that will upset China, Rubio's assertion that a disputed island chain belongs to Japan may offend Beijing more.

Xi, he said, "is asserting control over the East and South China Seas, through which more than half of global commerce passes each day.

"This is Beijing's way of gaining leverage over the world. It has unilaterally declared an 'air defense identification zone' over international waters and the Senkaku Islands, which are the territory of our ally Japan."

Ties between China and Japan have been strained over the Japanese administered islands in the East China Sea. Beijing also claims the chain, which it calls the Diaoyu islands.

The US government has been careful not to weigh in on the final status of the islands.

Zhu Haiquan, a spokesman for the Chinese embassy in Washington, urged all "relevant American politicians to honor the US commitment of not taking sides on issues relating to sovereignty, and refrain from making unjustifiable accusations."

"China's determination to safeguard its own sovereignty and territorial integrity is rock-hard and unquestionable," he said.