North Korea conducts live-fire drills near disputed sea border, South says

North Korea conducted live-fire artillery drills Tuesday near the countries' disputed western sea boundary, South Korean military officials said, in a possible indication of rising frustration in Pyongyang as it unsuccessfully pushes for outside aid.

Both Koreas regularly conduct routine artillery drills near South Korean islands and the North Korean mainland in the Yellow Sea. But they can be sensitive because of the disputed maritime line separating the countries.

Last month, South Korea fired artillery shells into the North's waters after North Korean shells from a live-fire drill landed south of the boundary. After South Korean drills in 2010, North Korea shelled a South Korean island, killing four.

A Defense Ministry official, speaking on condition of anonymity because of office rules, confirmed that the drills had begun but provided no other details.