South Korea fires rounds at North in response to shell

South Korea said it fired tens of artillery rounds towards North Korea on Aug. 20 after the North launched a shell towards a South Korean loudspeaker that had been blaring anti-Pyongyang broadcasts, as tension escalated on the peninsula.

North Korea did not return fire but later warned Seoul in a letter that it would take military action if the South did not remove the loudspeakers within 48 hours, the South's defence ministry said. 

In the letter, North Korea's armed forces called the South's propaganda broadcasts a "major challenge" to the North. 

South Korea said its detection equipment had spotted the trajectory of a suspected North Korean projectile launched at around 3:52 p.m. (0652 GMT), which did not appear to have damaged the loudspeaker or caused any injuries. 

South Korean President Park Geun-hye told top defence officials to "react firmly" to North Korean provocations, a spokesman quoted her as saying. South Korea's military raised its alert status to the highest level. 

"Our military has stepped up monitoring and is closely watching North Korean military movements," South Korea's defence ministry said. 

There was no mention of the firing in North Korean state media, which does not typically make immediate comment on events. 

The suspected North Korean shell landed in an area about 60 km (35 miles) north of Seoul in the western part of the border zone, the defence ministry said. South Korean residents in the area were ordered to evacuate, according to the South's Yonhap news agency. 

The projectile appeared to have landed in a mountainous area near a South Korean military base in the town of Yeoncheon, Yonhap said. 

The exchange of fire was the first between the two Koreas...