US President Barack Obama told China's President Hu Jintao on Saturday that Americans were "frustrated" and "impatient" at the pace of change in Beijing's economic policy.
Obama delivered the frank warning in talks on the eve of a major Asia-Pacific summit, a senior US official said, after the president earlier warned that China must "play by the rules" of international trade.
The president's direct language betrayed increasing US concern over the level of China's yuan currency, which critics say is kept artificially low to boost exports, and Beijing's observance of intellectual property standards.
The meeting took place amid rising domestic political pressure on Obama over China's trade record, voiced again by Republican candidates in a campaign debate on Saturday as the 2012 presidential election campaign gathers pace.
In a public appearance before their talks in a Honolulu hotel, Obama and Hu did not stray far from diplomatic niceties, but economic tensions were clear.
Obama "made it very clear that the American people and the American business community were growing increasingly impatient and frustrated with the state of change in China economic policy and the evolution of the US-China economic relationship," said Michael Froman, a US deputy national security advisor.
Obama said before the talks he wanted to discuss "efforts to jointly ensure that countries like Iran are abiding by international rules and norms" and said North Korea's nuclear program and non-proliferation would also come up.
"We are both Pacific powers and I think many countries in the region look to a constructive relationship between the United States and China as the basis for continued growth and prosperity," Obama said.
Hu, in a nod to fraught economic times that have spooked global markets, said the world was undergoing "complex and profound changes."
"There is growing instability and uncertainty in the world economic recovery. Under these circumstances, it is all the more important that the US and China increase their communication and cooperation."
Earlier at a meeting with CEO's, Obama was more frank over US differences with China, singling out China's record on intellectual property protection amid complaints from US corporations that their innovation and products are being unfairly compromised and copied.
"For us not to get that competitive advantage that we need in a large marketplace like China is not acceptable," Obama said.
"The bottom line is that the United States can't be expected to stand by if there is not the kind of reciprocity in our trade relations and our economic relationship that we need."
The President also noted the long-running dispute between the United States and China over currency and said most experts believed that the yuan was unfairly undervalued despite some appreciation this year.
"We want you to play by the rules, and currency is probably a good example," Obama said, paraphrasing his message to Chinese leaders, ahead of his first meeting with Hu since he welcomed him on a state visit in January.
Obama, who is hosting the Asia-Pacific Economic Cooperation (APEC) summit here, will move on later in the week to Australia and an East Asia summit in Bali, as part of America's effort to cement its role as a major Pacific power.
In the run-up to the APEC summit, China complained Washington was setting its goals too high on trade liberalization and lowering tariffs on green industries. It also suggested TPP entry requirements may prove too onerous for some Asian nations.
China got a hammering on Saturday during a Republican campaign debate in South Carolina.
Texas governor Rick Perry said that the "communist Chinese government will end up on the ash heap of history."
Republican front runner Mitt Romney meanwhile branded Beijing as a "currency manipulator" which was "stealing our intellectual property, hacking into our computers or artificially lowering their prices and killing American jobs."
Aides said Obama had made clear to Hu that criticism of China was broadening in the United States, though he did not appear to have directly referred to the rhetoric of those who are vying to take his job.