Washington: A day after their meeting at the White House, US President Barack Obama and visiting Chinese Vice President Xi Jinping exchanged polite warnings on trade-related issues.

Travelling to Milwaukee in Iowa, Obama said he would not stand by competitors like China that don't play by the rules, whereas Xi, addressing a meeting of business leaders, said America needs to respect China's core interests and concerns.

"I am not going to stand by when our competitors don't play by the same rules. It's not fair when foreign manufacturers have a leg up on ours just because they're getting heavy subsidies from their government," he said in his remarks at the Master Lock manufacturing facility in Wisconsin.

"So I directed my administration to create a Trade Enforcement Unit, and it's only got one job: investigating unfair trade practices in countries like China, making sure we've got an even playing field -- because when we've got an even playing field, I promise you, nobody is going to out-compete America.

"We've got the most productive workers on Earth. We've got the most creative entrepreneurs on Earth. Give us a level playing field, we will not lose," the US President said.

In Washington, Xi, on a five day US visit, said China and the United States should increase strategic trust and respect core interests and major concerns of each other.

"We in China hope to work with the US side to maintain close high-level exchanges. We hope to increase dialogue and exchange of views with the United States by making full use of our channels of communication, including the Strategic and Economic Dialogues, cultural and people-to-people exchanges, and military-to-military exchanges.

"By doing so, we can better appreciate each other's strategic intentions and development goals, avoid misinterpretation and misjudgement, build up mutual understanding and strategic trust, and on that basis, fully tap our cooperation potential," Xi said in his address to US-China Business Council and the National Committee on US-China Relations.

Until and unless the two countries respect each other's core interests and major concerns, Xi said the relationship between the two countries would not be smooth.

"History shows that when we properly handle each other's core and major interests, China US relations will grow smoothly. Otherwise, they will be in trouble," Xi said.

(Agencies)