The Republic of Korea fired dozens of shells on Thursday at the Democratic People's Republic of Korea after the DPRK lobbed a single rocket round at a ROK town near the world's most heavily armed border, the ROK's Defense Ministry said.

The Defense Ministry said in a statement that its artillery shells landed at the place where the DPRK had fired its rocket. There were no other immediate details from the military and no reports of injuries. It appeared that the DPRK did not respond to the ROK's returned fire.

The DPRK had previously threatened to attack ROK loudspeakers that have been broadcasting, for the first time in 11 years, anti-Pyongyang messages across their shared border. Pyongyang also restarted its own loudspeakers aimed at the ROK.

The DPRK told Seoul it was willing to end an ongoing conflict over anti-Pyongyang propaganda broadcasts, which it demanded that the ROK stop, according to ROK Unification Ministry.

The DPRK's Kim Yang-gon, secretary of the Central Committee of the Workers' Party of Korea, sent a letter saying the ROK broadcasts were a declaration for war but the DPRK was "willing to offer an exit to settle the current situation and improve the relations", the ministry said

About 80 residents in the ROK town where the shell fell, Yeoncheon, were evacuated to underground bunkers, and authorities urged other residents to evacuate, a Yeoncheon official said, requesting anonymity because he wasn't authorized to speak to the media.

In the nearby border city of Paju, residents were asked to stay home. On Baeknyeong Island near the disputed western sea boundary - the scene of several bloody skirmishes in recent years - residents in villages near a site where the ROK operates one of its loudspeakers were also evacuated, according to island officials.

The cross-border propaganda warfare followed accusations from Seoul that Pyongyang had planted land mines on the ROK side of the Demilitarized Zone that maimed two ROK soldiers earlier this month. Pyongyang has claimed that Seoul fabricated the evidence on the land mines and demanded video proof.

Last October, ROK and DPRK troops opened fire at areas near Yeoncheon, after ROK activists launched balloons there that carried propaganda leaflets across the border. The ROK returned fire, but no casualties were reported. Later in October, border guards from the two neighbors again exchanged gunfire along the border, without any casualties.

Before that, the DPRK and ROK tangled in a deadly artillery exchange in 2010, when DPRK artillery strikes on a ROK border island killed four ROK citizens. Earlier in 2010, 46 ROK sailors died when their ship sunk amid disputed circumstances.

The DPRK's army said recently in a statement that the ROK broadcasts were a declaration of war and that if they were not immediately stopped "an all-out military action of justice" would ensue.

Thursday's artillery exchange came four days after the ROK and the United States began annual summertime military drills that the DPRK calls an invasion rehearsal. Seoul and Washington say the drills are defensive in nature.

The ROK has said the two soldiers wounded from the mine explosions were on a routine patrol in the southern part of the DMZ that separates the two Koreas. One soldier lost both legs and the other one leg.

The two neighbors' mine-strewn DMZ is a legacy of the 1950-53 Korean War, which ended with an armistice, not a peace treaty.

AP - Reuters