North Korea conducted an artillery drill near the sea border with South Korea, startling South Koreans and making them prepare for a possible evacuation, officials said Saturday.

Later, North Korean’s official Korean Central News Agency hurled insults at South Korean President Park Geun-hye, calling her a “tailless, old, insane bitch” as it denounced her hardline response to the North’s recent long-range rocket launch and nuclear test.

South Korea shut down a factory park in North Korea that had been jointly run by the rivals. Seaoul also has started preparatory talks with the U.S. on deploying an advanced missile defense system in South Korea in attempts to tighten the screws on Pyongyang.

South Korean 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 early Saturday morning, an unnamed South Korea Defense Ministry official told the Associated Press.

According to Reuters, Baengnyeong is a few miles from the disputed Northern Limit Line border and less than 12 miles from the North Korean shore.

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.

The Associated Press contributed to this report.