South Korea's benchmark Kospi index tumbled by more than 6% on Thursday, with semiconductor stocks leading the decline, mirroring losses in the US chipmaker sector overnight.

The heaviest drags on the index were Samsung Electronics, SK Hynix, and SK Square, each dropping at least 6%. Foreign and institutional investors were net sellers of Kospi shares, while retail investors stepped in as net buyers.

The junior Kosdaq index also fell sharply, losing over 4% during the session.