Exactly six months until the opening ceremony of the Tokyo Olympics, organizers shot off fireworks and lit up the city's new five-ringed Olympic monument Friday.

With preparations largely on track and public interest in the games building despite remaining challenges, Tokyo Gov. Yuriko Koike marked the occasion at a ceremony that included five minutes of fireworks and both Tokyo Tower and Tokyo's Rainbow Bridge bathed in multicolored lights.

"The torch relay will start in March," Koike said. "And though the next six months are going to go by in the blink of an eye, please cooperate for the games' success."

Nearly 5 million tickets for the Olympics, accounting for roughly half of the total, have already been sold domestically after two phases of heavily subscribed lotteries.

Lagging facility construction for the Olympics and Paralympics is unlikely to make headlines again, with the last two of nine new venues in the Japanese capital expected to be completed by March and all 21 residential buildings in the athletes' village to be in place before the village opens on July 14.

As part of security preparations for the games, the Japan Coast Guard conducted a counterterrorism drill Friday on a passenger ship at Tokyo's Takeshiba Pier, close to the waterfront precinct where the athletes' village is under construction.

The Tokyo metropolitan government, meanwhile, held an emergency meeting after a second infection with a new coronavirus was confirmed in Japan.

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As the deadly virus spreads rapidly in China and beyond, Koike told reporters that the capital should "undertake both risk management and the Japanese way of hospitality."

There have been some other challenges as well. The most notable blemish in the Summer Games' buildup for local organizers has been the relocation of the marathon and race walks events to the northern city of Sapporo at the behest of the International Olympic Committee.

The IOC made the abrupt decision last October, citing concerns about the extreme summertime temperatures in Tokyo. The world body was spurred to move the events following the disastrous women's marathon at the world athletics championships in Doha, Qatar, a month earlier, which saw dozens of runners pull out with heat exhaustion.

The Tokyo Games organizers have scrambled to get their dates and courses in Sapporo settled but must still arrange transport and lodgings for some 2,000 athletes and staff.

Transportation issues within Tokyo, too, remain unresolved despite a number of options proposed by Tokyo, the government and organizers. At this month's IOC session, transportation solutions were, along with heat countermeasures, received special attention.

"This is going to be a big issue we will be dealing with right until the end," said Hideaki Nakamura, the organizing committee's game delivery officer.

Sports analytics firm Gracenote released its medal prediction on Friday, saying Japan will reach its target of a record 30 gold medals. According to the prediction, the hosts will claim 65 medals and finish on the medal table behind the United States, China and Russia, which could be banned from the games.

Russian athletes face the possibility of having to compete under the Olympic flag as individual athletes following a ban imposed by the World Anti-Doping Agency over alleged state-sponsored doping and coverups. Russia's anti-doping agency RUSADA has filed an appeal with the Court of Arbitration for Sport.

The Olympics will be held in Tokyo and nine prefectures across eastern Japan at 24 venues inside the capital and 17 outside, while the Paralympics will be in Tokyo and three other prefectures. The organizers have scheduled 56 test events in the run-up to both games to identify any issues and ensure smooth running.

The games will be a nationwide affair thanks to the 478 "host towns" across all 47 prefectures, welcoming athletes from 163 countries and regions for camps and cultural exchanges in a first-of-its-kind program.

The Japan segment of the 121-day torch relay for the Olympic flame, dubbed the "Flame of Recovery," will start on March 26 at the J-Village soccer training center in Fukushima Prefecture, which served as an emergency response headquarters during the 2011 nuclear crisis.

The flame will be lit using hydrogen including some produced in Namie, Fukushima Prefecture, as it travels through all 47 prefectures.

The Japan Air Self-Defense Force "Blue Impulse" aerobatic team on Friday drew the Olympic symbol in the sky over Matsushima Air Base in Miyagi Prefecture in a practice run for a ceremony to mark the arrival of the torch on March 20.

Along with holdovers from Tokyo's previous Olympics in 1964, such as Nippon Budokan for judo and karate, the venues inside the metropolis will be a mixture of legacy sites and cutting-edge facilities.

The completed 60,000-seat National Stadium will host the Olympic and Paralympic opening and closing ceremonies, along with athletic events and Olympic soccer. The 2020 centerpiece, with a nature-themed exterior, began operation on New Year's Day.

On Thursday, the official uniform of the Japanese national team to be worn by athletes at the games was unveiled.

Olympic minister Seiko Hashimoto, who competed in four winter games and three summer games as a speed skater and cyclist, hopes home advantage will help the athletes deliver.

"Of course people focus on how well athletes perform when competing in their own country," she said last week during a briefing organized for foreign media organizations in Tokyo. "In the Rugby World Cup last year, the Japanese team did so well in making it to the knockout stage, which really helped the entire nation get excited."