Obama added that millions of Chinese have risen out of poverty, and that could "not have been done were there not a stable trading system and world order underwritten in large part by our alliances."
Obama's remarks came a day after the United States and Japan announced a revised defense agreement that would allow Japan's Self-Defense Forces to take a more active role in regional security. The changes, which are relatively modest, allow Japan to act when U.S. forces are threatened by a third country.
The president acknowledged the tensions that have arisen between China and other Asian nations from maritime disputes in the South China and East China seas.
"But that is not an issue arising as a consequence of the U.S.-Japan alliance," he said. "Rather than resolve it through normal international dispute settlements, they are flexing their muscles. We've said to China what we would say to any country: 'That’s the wrong way to go about it.' "
Abe, meanwhile, was asked to address the issue of Japan's wartime use of "comfort stations," which forced as many as 200,000 women into sexual slavery during World War II. Abe's refusal to issue a full-throated apology has angered South Korea and China.
But Abe again declined to directly apologize or take full responsibility for Japan.
"I am deeply pained to think about the comfort women who experience immeasurable pain and suffering as a result of victimization due to human trafficking," he said. "This is a feeling that I share equally with my predecessors."
Abe emphasized that he has endorsed previous statements from Japanese leaders that acknowledged the country's role in the abuse. But he added that "throughout the history of the 20th century, women's dignity and basic human rights have often been infringed upon during wars."
During the first full day of Abe's visit, the two nations agreed to strengthen a wide variety of links on trade, military cooperation, cybersecurity, nuclear nonproliferation, anti-terrorism efforts, climate change and humanitarian assistance.
At the news conference, Obama and Abe also touted progress on the Trans-Pacific Partnership, a 12-nation free trade and regulatory pact in the Asia Pacific region that the president has called one of his top priorities.
Negotiations between the United States and Japan are nearing completion, with just a few outstanding issues, and both sides are hoping to come to agreement in a few weeks — which could give crucial momentum to the deal. However, Obama still must convince Congress to support the deal, and lawmakers are currently weighing "fast-track" legislation that would smooth the way for completion.
However, Obama faces stiff opposition from most Democrats, labor unions and environmental groups.
"It's never fun passing a trade bill in this town," Obama said, "because people are understandably concerned about the potential impact on specific industries and general concerns people have about globalization and technology displacing workers. But this will end up being the most progressive trade bill history."
The Abe visit is full of symbolism and historical echoes — a speech to Congress, a visit to the U.S. Holocaust Memorial Museum and a walk Monday through the Lincoln Memorial.
The United States and Japan share many of the same strategic concerns about a nuclear North Korea, a growing Chinese military and nuclear proliferation. With the approach of the anniversary this summer of the U.S. nuclear bombing of Hiroshima and Nagasaki, the two countries said that they "affirm that it is in the interest of all States that the 70-year record of non-use should be extended forever and remain convinced that all States share the responsibility for achieving this goal."
But much of the news conference focused on China. Asked about the Chinese-backed Asia Infrastructure Investment Bank, which aims to help smaller countries in the region, Obama rejected the notion that his administration had lobbied allies not to join the project — which is seen by some U.S. officials as a challenge to the United States' leadership in the region.
Although Japan has not entered the AIIB, several U.S. allies, including Britain and Germany, have joined. Obama said the project has potential but emphasized that Beijing must be transparent and accountable with the money and influence.
"China’s got a lot of money. They've been running a big surplus for a long time," Obama said. "To the extent China wants to put capital into development projects around the region, that’s a positive, a good thing. Let me be very clear and dispel the notion we were opposed or are opposed to other countries participating."