Rescuers were searching Wednesday for six people after an overnight landslide buried a small cluster of houses at the foot of a steep slope in southern Japan. The landslide, which occurred around 3:50 a.m., damaged four homes in Oita prefecture on Kyushu, the southernmost of Japan's four main islands, Japan's Fire and Disaster Management Agency said. Four people from one house have been confirmed safe, but six are missing from the three others, Japanese government spokesman Yoshihide Suga said. Aerial photographs from Japanese news media showed a denuded swath on a thickly forested mountainside. At the bottom, a huge mound of earth and tree trunks buried houses, blocked the road in front of them and spilled over into fields on the other side. Blue-suited rescue workers could be seen on top of the rubble. The cause of the landslide wasn't immediately clear. It occurred in a mountainous inland area known as Yabakei, which is famous for its fall foliage. Oita is also popular among tourists for its hot springs resorts.