YANJI, CHINA (REUTERS) - Residents of the Chinese border city of Yanji felt the jolt from North Korea's sixth and most powerful nuclear test but did not let it get in the way of a Sunday (Sept 3) of shopping and dining.
At a high-end downtown mall in the city of about 400,000, clothing store Uniqlo did brisk trade and there wasn't an empty table at a nearby Starbucks. Shoppers dawdled by promotional events to win Toyota Corollas and Sharp TVs.
"We all ran out of our apartments when it happened, we had no idea what was going on. We thought it might have been an earthquake," said Bai Jin, sitting in an outdoor square near Starbucks with his grandson.
North Korea said it had tested a hydrogen bomb which it declared a "perfect success" and said no radiation had leaked. "I don't really think about the possible effects of radiation, the tests are conducted underground," Bai said.
China's Nuclear Safety Administration nevertheless said it had begun emergency monitoring for radiation along the border and South Korea's Nuclear Safety and Security Commission said it was making checks.
Sunday's explosion was measured by the US Geological Survey at magnitude 6.3, which Japanese and South Korean meteorological officials said was around 10 times more powerful than previous North Korean nuclear detonations, and was followed by an aftershock.
Michael Spavor, director of the Paektu Cultural Exchange, which promotes business and cultural ties with North Korea, said he was eating brunch when he felt the building shake for about five seconds, followed by city air raid sirens.
Yanji is about 200km north of North Korea's nuclear test site at Punggye-ri, along a border area that has become increasingly sensitive as Pyongyang's diplomatic isolation grows and as China faces pressure to rein in its neighbour and ally over repeated nuclear and ballistic missile tests.
United Nations sanctions have expanded to ban North Korean exports of commodities including coal, iron ore and seafood, much of which was bought by China. The countries share a 1,420km border.
"I'm pretty worried about radiation because a lot of our food comes from North Korea. We used to eat a lot of seafood from North Korea but that's recently stopped," said Wu Tingting, who works at a local resort.
Residents have long grown accustomed to a heightened military presence in border areas. "I'm not too worried because I think China and North Korea have a pretty good relationship," Wu said.
Huang Tao, who works at a state-owned company in Yanji, found out about the nuclear test when his friends posted it on WeChat, and noted that Sunday is marked in China as the 72nd anniversary of Japan's surrender in World War Two.
"Kim Fatty the Third is just helping us celebrate by setting off a few fire crackers," he said, using a derisive nickname in China for North Korea's third-generation leader, Kim Jong Un. "It's just another ordinary Sunday in downtown Yanji. Nothing changes when there's a nuclear test."