President Obama was scheduled to begin a series of regional meetings here Friday that would focus on security issues and disaster relief and bring him face to face with top Chinese officials for the second time in a week.

Obama will be the first U.S. president to take part in the East Asia Summit, an annual forum of 16 nations that is expanding this year to include the United States and Russia.

At the summit, the United States and other countries are expected to press China to abide by “international norms” in regard to the South China Sea, a critical commercial shipping channel that is thought to contain valuable oil and minerals, administration officials said.

China has staked a claim to a large portion of the sea and backed it up with military confrontations aimed at cowing smaller rivals.

Obama has made China the focal point of his nine-day, four-city Asia Pacific trip, insisting at an economic summit in Hono­lulu last weekend that Beijing must “play by the rules” on international trade.

Chinese officials reacted defensively, telling reporters Tuesday that the South China Sea dispute should not be on the agenda for the Bali summit. After meeting with Chinese President Hu Jintao in Hono­lulu, Obama and his aides will meet with high-level Hu advisers here because Hu is not attending the summit.

In addition to participating in the summit, Obama will hold bilateral meetings with the leaders of India, the Philippines, Malaysia, Indonesia and Thailand. Aides said discussion topics will include how to help a region that has been hard-hit by massive tsunamis and earthquakes in recent years.

The president will leave Indonesia on Saturday, returning to Washington early Sunday.

Shortly after he arrived in Indonesia on Thursday evening local time, the White House announced private trade deals between U.S. manufacturers Boeing and General Motors and airline companies in Southeast Asia. The deals are worth $25 billion, the White House said, and could support up to 127,000 American jobs.

Earlier Thursday, Obama wrapped up a two-day visit to Australia with a speech to the Australian Parliament; a visit to a high school in the capital, Canberra; a solemn wreath-laying; and a lively address to Australian troops.

The speeches to lawmakers and soldiers were aimed at promoting a new U.S.-Australian military partnership, in which the United States will send groups of 250 Marines to Australia starting next summer for six-month company rotations.

The joint effort is the first step in the Obama administration’s foreign policy shift away from the wars in Iraq and Afghanistan, which the United States is winding down, toward a focus on economic growth and security in the Asia Pacific region.

Obama administration officials have characterized the new partnership with Australia as an opportunity for combined arms training, along with disaster relief and humanitarian aid exercises. The number of U.S. troops rotating through Australia will eventually grow to 2,500, and they will be housed at Australian facilities, officials said.

Brig. Gen. Ronald Baczkowski said Thursday that about 55 Marines from Norfolk arrived in Darwin, Australia, this week to work on small-arms training and infantry maneuvers.

“The concept of a rotational force is not new,” he said. “It’s just taken to the next step.”

Yet the agreement has alarmed Chinese officials. Although the number of troops who will be stationed here is small, the move has been accompanied by tough rhetoric.

In his parliamentary address, Obama said he made a deliberate decision for the United States to play a “larger and long-term” role in shaping the future of the region. All nations, he said, have an interest in the rise of a “peaceful and prosperous China. That’s why the United States welcomes it. . . . We will seek more cooperation with Beijing.”

But Obama added that the United States will “speak candidly to Beijing about the importance of upholding international norms and the respect for the basic universal human rights of the Chinese people.”

Australian Prime Minister Julia Gillard and opposition leader Tony Abbott praised Obama and the United States, saying they welcomed the expanded military alliance even though China is Australia’s largest trading partner.

“American world leadership may only be truly appreciated when it’s gone,” Abbott said. “None of us want to find out the hard way what a shrunken America looks like. A strong America means a safer world.”

In the end, Obama made the case that the United States’ presence as a strong “Pacific nation” will help ensure that certain rights that he said “stir in every human heart” — the freedoms of speech, press, assembly and religion, as well as the freedom of citizens to choose their own leaders — will be maintained.

“This is the future we seek in the Asia Pacific — security, prosperity and dignity for all,” Obama said. “That’s what we stand for. That’s who we are. That’s the future we will pursue, in partnership with allies and friends, and with every element of American power. So let there be no doubt: In the Asia Pacific in the 21st century, the United States of America is all in.”

In his brief remarks to the soldiers at the Royal Australian Air Force Base in Darwin, Obama paid tribute to the two countries’ 60-year alliance, which began during World War II.

He noted that it was in Darwin, which he called “Australia’s Pearl Harbor,” that U.S. and Australian troops suffered heavy losses after being bombed by Japanese aircraft. The destroyer USS Peary was sunk in the harbor of this base in Australia’s remote Northern Territory.

Citing collaboration by the two nations in Iraq and Afghanistan, Obama added: “Now, here in Darwin and Northern Australia, we’ll write the next proud chapter in our alliance.”