SEOUL » Sounds of explosions caused South Korean residents of a front-line island to prepare to evacuate early Saturday, but it was later determined the noise came from a North Korean artillery drill across the rivals’ disputed maritime border, officials said.

The false alarm was indicative of the high anxiety between the Koreas in the wake of the North’s recent long-range rocket launch and nuclear test.

North Korea’s official Korean Central News Agency hours later hurled insults at South Korean President Park Geun-hye, calling her a “tailless, old, insane female dog” as it condemned her hard-line response to the North’s recent actions.

The government of Park, who has been a frequent target of sexist comments from the North, shut down a factory park in North Korea that had been jointly run by the rivals. Seoul also has started preparatory talks with Washington on deploying a sophisticated missile defense system in South Korea in attempts to tighten screws on Pyongyang.

South Korea’s front-line soldiers near the northwest island of Baengnyeong heard several explosions and also saw flashes from what the military believes were shells fired from North Korean coastal guns at around 7:20 a.m., said an official from Seoul’s Defense Ministry, who didn’t want to be named, citing office rules. No North Korean projectile flew south of the maritime border, he said.

An official from the county that governs the island said that residents didn’t evacuate although fishing boats returned to their ports. She said that passenger vessels from the island and the mainland port of Incheon were operating normally.

Meanwhile, Seoul’s Defense Ministry said Saturday that the military completed its search operations for debris from the North Korean long-range rocket that was launched into orbit Feb. 7.

The military said it was unlikely that there were any more crucial parts left to be found in South Korean seas. The ministry said that the navy recovered two pieces of debris presumed to be from the launch at an island off the country’s western coast on Thursday and Friday.

South Korean officials believe the North deliberately blew up the rocket’s first stage after burnout to prevent South Korea from retrieving debris.

North Korea said it launched an Earth observation satellite, but South Korea, the U.S. and the U.N. said it violated a ban on Pyongyang’s missile technology.