South Korea saw its ranking plunge on a famed global peace index this year on the back of the North’s persistent military threats that heightened cross-border tension, a report said Thursday.

The index by Institute for Economics and Peace, a non-profit think tank headquartered in Sydney, put South Korea in 52nd place among 162 countries, down six notches from last year.

The North moved up two spots to rank 153rd.

On a 1-5 scale, where a lower score means greater peace, South and North Korea fetched 1.849 and 3.071 points this year, respectively, based on 22 indicators including relations with neighbors, military spending and the level of violent crimes.

Iceland again topped the list with 1.189 points, followed by Denmark with 1.193, Austria with 1.200 and New Zealand with 1.236.