A Goesan County official makes an on-site inspection following a report that roof tiles fell off a house in the county, 110 kilometers south of Seoul last Saturday. (Yonhap)

An aftershock of magnitude 2.9 struck South Korea's central county of Goesan on Tuesday following a 4.1 magnitude quake last week, authorities said.

No damage or casualties have been reported so far, according to the Central Disaster and Safety Countermeasures Headquarters.

The aftershock occurred in the area northeast of Goesan in North Chungcheong Province at 2:07 a.m. Tuesday, with an estimated depth of 14 kilometers, they said.

A total of 21 aftershocks have occurred since Saturday's earthquake. It was the strongest earthquake to hit the Korean Peninsula this year. (Yonhap)