No South Korean casualties have so far been reported in the series of deadly earthquakes that struck Japan this week, an official said Saturday.

A 7.3-magnitude temblor hit Kumamoto Prefecture on the southern island of Kyushu at around 1:25 a.m. Saturday, less than two days after a 6.5-magnitude quake struck the same region, leaving a total of 18 people dead and more than 1,800 injured, according to Japanese authorities.

"So far, we haven't received reports of any harm to South Koreans," Park Ki-jun, deputy chief of the South Korean consulate general in Fukuoka, told Yonhap News Agency by phone.

South Korean tourists have been calling the consulate general to seek help amid a suspension of flights and traffic controls, he said. (Yonhap)