Japanese worshippers prayed for the safety of themselves and their families on Sunday by walking barefoot with Buddhist monks over smouldering coals at an annual festival near Mt. Takaosan.

The fire-walking was more tense than usual because participants were required to wear masks and maintain social distancing due to the coronavirus pandemic. The festival was also limited to 1,000 participants. Last year, it wasn't open to the public because of the Covid-19 pandemic.

"Passing your body through the flames cleanses your soul and delivers your prayers to Buddha," said Koshou Kamimura, a Buddhist monk from Takaosan Yakuouin Temple.

"Historically, Mt. Takaosan is an important place to pray for deliverance from plagues, so I felt we should hold the festival this year with certain precautions."

The festival, called hiwatari matsuri in Japanese, has a history of about 50 years at Mt. Takaosan.

The monks set fire to wood and Japanese cypress leaves, creating an intense bonfire. The monks then doused the flames with water, collected the embers and laid them out in two strips, over which they walked barefoot while chanting.

Worshippers followed the monks, wearing masks due to the coronavirus. Some monks carried small children over the embers as dark smoke billowed into the air.

Tokyo is preparing to host the Summer Olympics this year, delayed from 2020 because of the coronavirus, with domestic opinion polls showing people favour limiting the number of spectators at the games.

"Coronavirus infections are spreading globally, so I prayed that it doesn't spread any further," said Eriko Nakamura, 46, as Buddhist monks chanted in the background.

"The fire-walking event is held outside and there are restrictions on the number of participants. When it comes to the Olympics, it will be held indoors, so I hope they can limit the number of spectators by half."

The number of coronavirus cases in Japan is relatively low compared to other countries such as the United States, although some areas including Tokyo are still under a state of emergency, with the country experiencing a third wave of the pandemic.