YEONPYEONG ISLAND, South Korea – South Korea fired live artillery in a drill from a front-line island today and launched fighter jets to deter attacks after North Korea warned of catastrophic retaliation for the maneuvers.

There was no immediate sign of any North Korean military response to the drill, which lasted about 90 minutes. The South evacuated hundreds of residents near its tense land border and sent residents of islands near disputed waters into underground bunkers amid soaring fears of war.

The exercises came nearly nearly a month after the North responded to earlier maneuvers by shelling Yeonpyeong island, killing two marines and two civilians in its first attack targeting civilian areas since the 1950-53 Korean War. It had said it would respond even more harshly to any new drills from the Yellow Sea island.

U.N. diplomats meeting in New York failed to find any solution to ease fears of renewed warfare on the Korean peninsula.

Hours later, Seoul’s Defense Ministry said the drills were under way on Yeonpyeong, a tiny enclave of fishing communities and military bases about seven miles from North Korean shores. An Associated Press photographer heard the sounds of explosions start up, pause about an hour later and then start up again.

The North considers waters around Yeonpyeong its own territory. Similar drills on Nov. 23 sparked the North’s artillery barrage, after what it says were clear warnings to the South to halt the firing. The North warned of a “catastrophe” if South Korea went ahead with new drills.

South Korea’s military said ahead of today’s drills that it would “immediately and sternly” deal with any provocation by the North. Fighter jets flew over South Korean airspace on a mission to deter North Korean attacks, a Defense Ministry official said. He spoke on condition of anonymity, citing department rules.

Residents, local officials and journalists on Yeonpyeong and four other islands were ordered to evacuate to underground shelters because of possible attacks by North Korea, Ongjin County government spokesman Won Ji-young said.

Hundreds of South Koreans living near the tense land border with North Korea were either evacuated to bomb shelters or taken to areas farther south ahead of the drills, local officials said.

On Yeonpyeong, residents filed into an underground shelter after authorities announced the drill and huddled on the floor as a South Korean soldier showed them how to use a gas mask, according to footage shot by Associated Press Television News.

“I feel the same as last Nov. 23, when North Korea fired artillery at us,” said Oh Gui-nam, a 70-year-old island resident. “My emotions are all tangled up.”