Lee Myung-bak, the South Korean President, stressed the need to bolster defenses against threats from the North during a visit to an island near the tense maritime limit amid mounting cross-border tensions.

Mr. Lee reiterated the need to defend the maritime border “to the last man” alluding to the shelling of the Yeonpyeong island two years ago, which killed two South Korean soldiers and two civilians and prompted Seoul to fire its own artillery.

“The reason that we build up the military is not only to bolster our means to retaliate but to prevent the North’s provocation,” Yonhap news agency quoted Mr. Lee as saying.

Mr. Lee also inspected an anti-artillery radar unit and artillery company on the island. “If North Korea provokes us, we have to retaliate strongly. We always have to remain vigilant”. The president announced an annual, large-scale military exercise including “drills against infiltration, regional provocations or an all-out war by North Korea,” a defense ministry told AFP.

This comes as tensions in the Korean peninsula escalate following intrusions by North Korean fishing boats, defections and an arms race propelled by Seoul’s recent acquisition of longer-range missiles approved by the US.