Japanese police said on Wednesday they arrested a South Korean man two weeks after a small explosion struck the controversial Yasukuni war shrine in Tokyo.
The 27-year-old man returned to Tokyo from South Korea on Wednesday and was arrested by Tokyo Metropolitan Police, according to several reports, including from national broadcaster NHK and Jiji Press.
Police said only that they arrested Jeon Chang-Han on the charge of illegal entry into the shrine, but declined to comment whether the case was linked to the explosion.
"The suspect entered the inner premises of Yasukuni Shrine with no justifiable reason" sometime between November 22 and 23, a police spokesman said, reading from a prepared statement.
The South Korean government said it was watching the situation.
"We will closely monitor the result of the investigation by the Japanese authorities and will provide necessary consular assistance to the person," the country's foreign ministry said in a statement.
The shrine in central Tokyo honors millions of Japan's war dead, including several senior military and political figures convicted of war crimes after World War II and is a flashpoint for clashing nationalist sentiments in Northeast Asia.
Visits to the shrine by senior Japanese politicians routinely draw an angry reaction from China and South Korea, which see it as a symbol of Tokyo's militaristic past.
Police approached Jeon as he arrived at Tokyo's Haneda airport before arresting him on a charge of illegal entry, the reports said.
Jeon denies the allegation, according to Japanese media.
During the November 23 incident, in which no one was hurt, a loud bang was heard and smoke was seen rising from a public bathroom on the shrine's leafy grounds.
At the time the shrine was hosting an annual harvest festival that attracted a larger-than-usual number of visitors on a national holiday.
Police found batteries, wire and pipes packed with what appeared to be gunpowder, media said. A bomb unit initially rushed to the scene.
Police later said the suspect was believed to have gone to South Korea after the explosion, according to reports.
The shrine has been a target of occasional attacks by activists.
A South Korean national was charged two years ago for attempting to set fire to the shrine, while a man was also arrested in December 2014 for suspected arson there, according to media.