WASHINGTON — The fun and flattery are largely over for President Donald Trump as he embarks on his third overseas trip in a month, this time facing a flurry of international crises, tense negotiations and a growing global to-do list.

Trump heads first to Osaka, Japan, for the annual Group of 20 summit, then to South Korea for consultations on North Korea’s nuclear program. The agenda for his four-day trip is as laden with hazards for the president as it is light on the ceremonial pomp that marked his recent state visits to Japan and the United Kingdom.

The showdown between the U.S. and Iran, a trade war with China and the threat of fresh election interference by Russia are some of the issues confronting the American leader who has shown little patience for the subtleties of global interactions and whose administration has struggled to grapple with simultaneous challenges.

Trump will meet one-on-one with at least eight world leaders on the summit’s sidelines as he faces mounting pressures to deliver results on a lengthy roster of global concerns. But White House officials are playing down prospects of specific accomplishments in what will almost certainly be Trump’s most consequential trip of the year.

Trump said before departing Wednesday that he’d be meeting “competitors” from other nations, adding, “That’s OK. We’re doing great. We’re doing better than any of them.”

His calendar includes sit-downs with Russian President Vladimir Putin, Chinese President Xi Jinping, Turkey’s Recep Tayyip Erdogan and Saudi Crown Prince Mohammed bin Salman, all of whom have authoritarian tendencies, as well as disquieted allies, including Germany’s Angela Merkel, and more contented ones such as Japanese Prime Minister Shinzo Abe.

Trump left Washington days after pulling back from the brink of armed conflict with Iran and as he trades threats over its nuclear program and support for terror groups. With Iran threatening to breach uranium enrichment limits set in the 2015 nuclear accord as soon as Thursday, Trump will be asked to articulate his strategy for containing Iran to skeptical world leaders after pulling the U.S. from the deal last year.

“The leaders are going to be pressing the president for clarity and then to get into a unified allied approach to the challenge, and it’s just simply unclear to me whether we have that policy or that approach,” said Heather Conley, director of the Center for Strategic and International Studies’ Europe program.

Trump will also find himself face-to-face with Putin for the first time since special counsel Robert Mueller’s investigation ended without finding evidence that the Trump campaign criminally conspired with Russia during the 2016 election. It will also be their first meeting since their summit in Helsinki in July 2018, when Trump declined to side with U.S. intelligence agencies over Putin on the question of election interference, leading to an uproar at home and abroad.

Trump told reporters as he left the White House that he expects a “very good conversation” with Putin but added that “what I say to him is none of your business.”

White House officials said Trump would warn Putin to refrain from interfering in U.S. elections, though Trump has been criticized for joining with Putin in attacking Mueller’s probe, and advisers worry he may do so once again.

With Xi, a senior administration official said, Trump’s aim will be rebooting trade talks between the countries after they collapsed earlier this year. In an interview with Fox Business Network, Trump threatened again to impose stiffer tariffs on Chinese imports to the U.S. if talks remain stalemated. But officials in both nations are looking for an off-ramp as concerns mount about the economic impact of the yearlong trade war.