South Korea’s leading presidential candidates sharply criticized North Korea for its attack on Yeonpyeong Island, as the nation marks the 11th anniversary of the deadly artillery shelling near the inter-Korean maritime border.

Democrat Lee Jae-myung and conservative Yoon Seok-youl both referred to the attack, which killed two civilians and two ROK soldiers, as a “provocation” and promised decisive action against any future assaults.

“Eleven years have passed since … North Korea’s illegal ambush,” Yoon wrote in a social media post on Tuesday, describing the shelling as a “merciless provocation against humanity.”