Updated at 10:10 a.m. ET

With news from the special counsel's probe into Russian interference in the presidential election still swirling in Washington, President Trump is leaving Friday on his longest foreign trip to date.

The Asian odyssey will take him to five countries and two international summits. Trade issues and North Korea's nuclear threat are likely to dominate the discussions. Here's a quick primer on what to watch for at each stop:

Japan

After a stopover in Hawaii, Trump arrives in Tokyo where he'll meet with Japanese Prime Minister Shinzo Abe, as well as American and Japanese service members. He'll also meet with the relatives of Japanese citizens who have been held prisoner in North Korea. Japan is alarmed by the increasingly aggressive moves of North Korea, including tests of ballistic missiles that have flown over Japanese territory.

During the campaign, Trump said he'd be willing to see Japan develop its own nuclear arsenal, upending decades of nonproliferation policy. Since taking office, Trump has reaffirmed the U.S. commitment to defend Japan, though aides say there is room for Japan to upgrade its own defense.

On a lighter note, Trump and Abe are both avid golfers, and they're expected to play a round together in Tokyo.

South Korea

Trump will meet with South Korean President Moon Jae-in and deliver a speech to the National Assembly, where he'll urge other countries to ramp up the pressure to halt North Korea's nuclear program.

"President Trump will reiterate the plain fact that North Korea threatens not just our allies — South Korea and Japan — and the United States," national security adviser H.R. McMaster said in a briefing on Thursday. "North Korea is a threat to the entire world, so all nations of the world must do more to counter that threat."

Trump will also visit Camp Humphreys, a newly expanded military base 40 miles south of Seoul, which will eventually house many of the 28,500 U.S. troops in the country. South Korea paid most of the cost of developing the $11 billion base, and the Trump administration calls it a great example of "burden sharing."

During the campaign, Trump questioned whether South Korea and other allies contribute enough to their own defense, although South Korea's defense spending is relatively robust — about 2.5 percent of its total economy. President Moon has also called for eventually giving the South Korean military "operational control" of forces on the peninsula, including Americans, in the event of a conflict. The transfer of operational control has repeatedly been postponed.

Although U.S. presidents visiting Korea often tour the demilitarized zone, Trump will not do so. Aides cited time constraints and the president's visit to Camp Humphreys.

China

In China, Trump will meet with President Xi Jinping, who just concluded a Communist Party Congress that strengthened Xi's grip on power and enshrined his policies in the party constitution.

Trump will once again urge China to use its economic leverage to put the brakes on North Korea's nuclear program. Aides say the administration is pleased with steps China has taken so far — such as halting purchases of North Korean coal — but add that all countries need to do more. In September, China's central bank ordered financial institutions throughout the country to stop doing business with North Korea.

"China is definitely doing more. But obviously it's not enough," McMaster said. "This isn't the United States or anyone else asking China to do us a favor. China recognizes it is clearly in China's interest — and all nations' interest — to denuclearize the peninsula."

Trump also wants to press China for more balanced trade. He complained repeatedly during the campaign about the U.S. trade deficit with China, which topped $300 billion last year. The administration argues that China unfairly restricts imports from the U.S. In October, the Commerce Department ordered anti-dumping tariffs on imports of Chinese aluminum foil. Despite Trump's combative rhetoric, the administration has so far held off on imposing more severe trade penalties. Trump has suggested he'll look more favorably on China's trade moves if Xi cooperates on North Korea.

Vietnam

In Danang, Vietnam, Trump will attend the Asia-Pacific Economic Cooperation summit, which brings together leaders of 21 countries around the Pacific Rim. He'll also speak to a gathering of corporate executives being held alongside the summit. Trump is expected to discuss the important role Asia plays in the U.S. economy as well as the U.S. commitment to a free and open "Indo-Pacific region."

Those themes echo pronouncements from former President Barack Obama, who tried to boost America's profile in the region, both militarily and economically. In one of his first acts as president, though, Trump withdrew the U.S. from a 12-nation trade pact at the center of Obama's pacific agenda. Trump's APEC speech will be an opportunity for the president to offer an alternative vision for U.S. engagement in the region.

Russian President Vladimir Putin will also attend the APEC summit. The White House has not said whether Trump and Putin will meet one-on-one.

On the fashion front, APEC tradition calls for a "family photo" of leaders wearing matching outfits based on the host country's indigenous garb. (You can see a gallery from past summits here.) Vietnam plans to stick to this tradition, though it's not known if Trump will actually don the local costume.

Trump will also travel to Hanoi for meetings with Vietnamese leaders. He'll be in Vietnam on Nov. 11, when the U.S observes Veterans Day.

Philippines

Trump will attend a summit of Southeast Asian nations in Manila and meet one-on-one with President Rodrigo Duterte. The Philippines leader has drawn international scrutiny for his crackdown on drug trafficking, which critics say includes thousands of extra-judicial killings. Last year, Obama canceled a planned meeting with Duterte after the Philippine leader warned him not to raise the human rights issue and referred to Obama as a "son of a whore."

In addition to the 10-nation ASEAN summit, Trump is now also planning to attend a broader East Asia Summit that follows it. He had initially planned to skip that second gathering, which some observers saw as a missed opportunity for him to demonstrate U.S. commitment to the region. On Friday, as he departed the White House to begin his journey to Asia, the president announced a last-minute extension of the trip so he could attend that summit after all.

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