Top diplomats from Europe and North America were arriving Sunday in this hot spring resort town to discuss the world’s most intractable crises, including ways to end Russia’s war in Ukraine, confront China’s aggression toward Taiwan and lure North Korea back to nuclear disarmament talks. They will dive right in, with a private working dinner Sunday spotlighting China and North Korea. But even before the Group of Seven foreign ministers’ talks began, outside events threatened to overshadow the diplomacy, including questions about U.S. intelligence leaks that cast doubt over crucial alliances, and security worries after someone threw an explosive device at the Japanese leader during a campaign event. Japan is eager to use a smoothly run G-7, which includes a host of gatherings on climate, finance and other issues ahead of a leaders’ summit next month in Hiroshima, to pursue a stronger unified front against what Tokyo and other democracies see as Russian, Chinese and North Korean aggression. Amid widespread skepticism that the United Nations, which is often paralyzed by the oversized power on the Security Council of Russia and China, can do anything about these issues, many will be watching to see what, if anything, G-7 ministers from Japan, the United States, the United Kingdom, France, Germany, Canada, Italy and the European Union might do. Security is tight in Karuizawa, but Japan has been forced to address safety concerns after a young man threw an explosive device toward Japanese Prime Minister Fumio Kishida on the eve of the diplomats’ arrivals. Kishida was uninjured Saturday and continued campaigning, but the attack is an unwanted development for Tokyo amid a lingering security debate over the assassination nine months ago of former Japanese Prime Minister Shinzo Abe. “Starting with the summit, we have to make every effort to ensure security and safety … (as) dignitaries from all over the world gather,” Kishida told reporters Sunday. The three-day talks will also see the first real test of the Biden administration’s assertion that there has been minimal damage from the disclosure of highly classified documents related to the war in Ukraine and U.S. views of its allies and partners. Before traveling to Japan, U.S. Secretary of State Antony Blinken said Saturday from Hanoi that he had heard no concerns from allies, but the revelations will loom over the G-7 meeting, the first major international diplomatic conference since the documents were discovered online and made public. On the diplomatic front, the talks, which end Tuesday, will be dominated by worries over the Russian leader’s threats to use tactical nuclear weapons as his forces struggle in Ukraine, China’s increasing belligerence toward Taiwan, the self-governing island Beijing claims as its own, and North Korea’s record-setting run of illicit weapons tests. Some observers expect that Japan and other nations might use the G-7 to announce an increase in aid to Ukraine. “As Russia’s invasion of Ukraine has been shaking the foundation of the international order, the international community is now at a historic turning point,” Japanese Foreign Minister Yoshimasa Hayashi said ahead of the meeting. “I will lead discussions as chair of the meeting and show the G-7’s strong determination to absolutely reject attempts to change the status quo by force, and Russia’s threat of nuclear weapons or their use, while defending the rules-based international order.” Though diplomats from Beijing won’t be present in Japan, China’s rapid military rise will also play a large part in discussions. China recently sent planes and ships to conduct a simulated encirclement of Taiwan, and has seen in recent years a rapid jump in its nuclear warheads, a tougher line on its claim to the South China Sea and increased comments from its leader, Xi Jinping, painting a scenario of impending confrontation. Japan, in response partly to China’s rise, has made a major break from its self-defense-only post-World War II principles, as it works to acquire preemptive strike capabilities and cruise missiles to counter growing threats. Diplomats will also be looking to find ways to restart diplomacy aimed at pressuring a hostile North Korea to return to disarmament negotiations. Since last year, North Korea has test-fired around 100 missiles, including intercontinental ballistic missiles that showed the potential of reaching the U.S. mainland and a variety of other shorter-range weapons that threaten South Korea and Japan.