By James Pearson

SEOUL (Reuters) - North Korea said it will conduct live fire drills on Tuesday in two areas near a disputed sea border with South Korea, the South Korean ministry of defence said on Tuesday.

North Korea conducted similar drills in late March when it fired more than 500 artillery rounds near the Northern Limit Line (NLL), a disputed maritime border that has been the de facto sea border since the 1950-53 Korean war.

More than 100 rounds landed south of the border, prompting South Korea to fire hundreds of rounds back into the North's waters.

The Northern Limit Line is an extension of the land border between the two Koreas, stretching into the sea west of the Korean peninsula.

It curves northward, effectively isolating five remote South Korean-controlled islands from the mainland, the furthest of which is closer to Pyongyang than Seoul.

South Korean military officials told local residents to seek cover in one of many shelters dotted around the small fishing villages and farming hamlets on the islands, local cable news network YTN said. South Korean increased its military presence on the islands following the 2010 bombardment of Yeonpyeong island by the North, which it said was in response to South Korean artillery drills.

(Additional reporting by Jack Kim; Editing by Michael Perry)