For more on President Obama's tour of Asia, check out CNN's White House blog, The 1600 Report.
(CNN) -- American and South Korean negotiators failed to reach agreement on a new trade pact during President Barack Obama's visit to Seoul, creating new delays and obstacles for an accord that the White House has said could translate to an additional $10 billion in U.S. exports and 70,000 American jobs.
A long-running dispute over U.S. access to Korea's auto and beef markets was largely responsible for the failure, according to the White House.
Obama tried to put a positive spin on the setback during a joint news conference with South Korean President Lee Myung-bak.
"We have asked our teams to work tirelessly in the coming days and weeks to get this completed, and we are confident that we will do so," he said.
Reaching a deal "could be a win for the overall economic partnership between our two countries by bringing us closer together, allowing us to benefit from each other's innovations, and ensuring strong protections for workers' rights and the environment."
Lee has agreed to send a team to Washington to continue work on the trade pact. Among the hurdles negotiators are trying to overcome: Korean conglomerates known as chaebols, which have kept a firm grasp on the union-strong country's marketplace, drawing complaints from foreign companies that have tried to do business there.
Obama is in South Korea for the G-20 summit, which is meeting Thursday and Friday to try to stabilize the world's financial markets. His trip is part of a 10-day Asia tour that is aimed at strengthening the United States' trade and military ties with a region that has thrived economically.
Widespread protests are expected at the summit, for which South Korea has mobilized its largest security force ever, according to the Yonhap news agency. A total of 50,000 police and riot police are being deployed, authorities told Yonhap.
A number of South Korean union and civic groups are gearing up for large protests against the G-20, while other groups are planning unrelated rallies in hopes of drawing international media attention.
Before meeting with Lee and holding the joint news conference, Obama paid tribute Thursday to American troops who 60 years ago fought a communist regime that he said continues to be a provocative threat to peace in the region.
Speaking on Veterans Day at the U.S. Army garrison in Yongsan, South Korea, the president drew parallels between America's ally and North Korea.
"Today, the Korean peninsula provides the world's clearest contrast between a society that is open and one that is closed; between a nation that is dynamic and growing, and a government that would rather starve its people than change," he said in remarks prepared for U.S. military personnel and members of their families.
Obama paid tribute to generations of men and women who served in the U.S. military. He also praised South Korean troops and Americans who fought during the 1950-53 Korean War.
The president, who made a reference to South Korea's claim earlier this year that North Korea sank one of its navy vessels, said the United States "will never waver in our commitment to the security of the Republic of Korea."
North Korea has another path besides pursuing nuclear weapons, Obama said.
"If they choose to fulfill their international obligations and commitments to the international community, they will have the chance to offer their people lives of growing opportunity instead of crushing poverty," he said.
Obama repeated that stance at the joint news conference with Lee.
The U.S. president's visit to Seoul also included a meeting with Chinese President Hu Jintao, who has stood fast against pressure to let his country's currency float freely.
Obama and Hu started private discussions Thursday after briefing making comments to reporters.
"The U.S.-China relationship, I think, has become stronger over the last several years, as we've been discussing a whole range of not only bilateral issues but world issues," Obama said. "And as two leading nuclear powers, obviously we have special obligation to deal of nuclear proliferation. As two of the world's leading economies, we've got a special obligation to deal with ensuring strong balance and sustained growth."
China's president spoke more generally.
"The Chinese side stands ready to work with the U.S. side to increase dialogue, exchanges and cooperation so that we can move forward the China-U.S. relationship on a positive, cooperative and comprehensive track," Hu said. He also thanked Obama for inviting him to visit the United States early next year.
"I hope and do believe that the visit will be successful," Hu said.
Officials in China and the United States have accused the other of manipulating its currency at the expense of other economies. And the G-20 has acknowledged that the global economic recovery is advancing in "a fragile and uneven way."
Grappling with a troubled U.S. economy, the Obama administration has highlighted the strengthening of economic and military ties during the president's Asia tour. Obama started his trip with a three-day stay in India, before heading to Indonesia and then to South Korea.
Obama also met with German Chancellor Angela Merkel on Thursday in Seoul.
Germany has slammed the U.S. Federal Reserve's decision last week to pump $600 billion into the economy. The move makes U.S. exports more competitive and has been blamed for pumping "hot money" into other economies -- money that can help fuel financial bubbles.
The United States has defended the move, describing it as necessary to jumpstart its economy. Americans, facing heavy debt and job uncertainty, have been reluctant to spend. Countries such as Germany need U.S. consumers to keep buying, Obama said while taking questions during his news conference with Lee.
"We want to make sure we're boosting growth rates at home and abroad," said Obama, describing the United States as an economic engine for the world.
Germany consumes relatively little and exports heavily. It has one of the world's largest trade surpluses.
At the Seoul summit, G-20 leaders are expected to focus on the global economic recovery and mechanisms to ensure balance and sustainable growth.
Collectively, the Group of 20 accounts for about 85 percent of global economic output. The 1997 Asian financial crisis prompted the creation of the group. The G-20 includes industrialized nations and developing economies, which focus on economic issues and economic policy coordination.
"If you look at the trend lines in the 21st century, the rise of Asia, the rise of individual countries within Asia, is one of the defining stories of our time," Ben Rhodes, deputy national security adviser for strategic communications said ahead of Obama's Asia trip.
The president will head back to the United States on Sunday.