SEOUL, Oct 29 — North Korea fired an unknown projectile off its east coast on Thursday, Seoul's defence ministry said, less than a week after South Korea proposed talks over a growing border row.

Japan's defence ministry separately confirmed the launch of what it said "appears to be a ballistic missile".

"The North fired an unidentified projectile into the East Sea," South Korea's military said, referring to the body of water also known as the Sea of Japan.

Thursday's launch comes against the backdrop of growing tensions over a landmine explosion along the heavily fortified border between the two Koreas that saw three South Korean soldiers wounded.