Hundreds of Japanese on Saturday flocked to an airport and a hotel in Tokyo to get a glimpse of U.S. President Donald Trump who arrived in Japan on a state visit as authorities stepped up security to its maximum level.

Over 500 people swarmed into an area on the fifth floor of Tokyo's Haneda airport, using their cameras and smartphones to capture the arrival of Trump and first lady Melania as they got off Air Force One.

"I saw Air Force One for the first time and it was huge. It was worth the three-hour wait," said Mitsuhiro Nakayama, 38, who came from Utsunomiya, about 100 kilometers north of the airport.

For security reasons, authorities banned the use of trash boxes and coin lockers in areas where non-passengers can enter and closed its observation decks a few hours before and after the U.S. plane's landing at the airport.

Elsewhere across Tokyo, security was tight, with up to around 25,000 police officers, unseen during past U.S. presidential visits, being mobilized through Trump's departure on Tuesday.

Tokyo police have been ramping up patrols around the clock and limiting road traffic.

Japan is hosting the Trumps as the first state guests under the new imperial era Reiwa that began on May 1 with the enthronement of Emperor Naruhito.

Trump, together with his wife, will be received by the emperor and Empress Masako on Monday ahead of a summit with Prime Minister Shinzo Abe. Before that, he will play golf and watch sumo with Abe on Sunday.

A throng of people carrying smartphones, including passers-by, also waited around a Tokyo hotel in front of the Imperial Palace as Trump's motorcade arrived at around 7 p.m.

"I didn't recognize his face because he was too far from here but it was indeed a once in a lifetime experience," said Yoichi Nagai, 50, from Ushiku, Ibaraki Prefecture, who was there while jogging around the palace.

The iconic 634-meter Tokyo Skytree tower in the capital was lit up in blue, white and red -- the three colors representing the U.S. national flag. It will be wrapped with the special colors between 6:45 p.m. and midnight for three days through Tuesday.

A woman in her 50s visited the tower with her husband after she learned about the event.

"Sumo (to be watched by Trump) is getting a lot of attention and it will be a difficult task to maintain security," said the woman from Tokyo's Koto Ward.