North Korea threatens 'merciless strike' against the south A group of North Korean defectors plan to carry out the leafleting exercise on October 22 at 11:30am (0230 GMT) at the border near the town of Paju, around 60 kilometres (35 miles) north of Seoul. Such exercises are relatively common and North Korea has threatened action in the past, but Friday's statement was unusually strong with its specific naming of the time and location, coupled with the evacuation warning. South Korea responded swiftly with Defence Minister Kim Kwan-Jin promising military retaliation in the event of any attack. "If that happens, we will strike back at the origin of fire," Kim was quoted as saying by Yonhap news agency. The group planning Monday's leafleting, Fighters for a Free North Korea, said they had no intention of calling off the event. "We'll never buckle to threats from North Korea," the head of the group, Park Sang-Hak, told AFP. "We will push through with it and stick to the plan down to the minute," Park said. During his visit to Yeonpyeong island on Wednesday, Lee had told troops stationed there that they should "fight to the death" to protect the border and "retaliate strongly" in the event of any North Korea provocation. There have been widespread concerns in the South that Pyongyang may try to instigate a military clash that would temporarily destabilise the Korean peninsula in the run up to South Korea's presidential election in December. Some South Korean analysts played down the warning from the North, saying its main aim was psychological. I think this is a bluff. I don't think they mean to actually target and shell the area," Kim Yong-Hyun, a professor at Dongguk University, told AFP. "It could be an indirect reaction to what President Lee said yesterday and the North is also seeking to drive wedges between conservatives and liberals ahead of the presidential poll," Kim said. On Wednesday, South Korea had announced an annual, large-scale military exercise aimed at countering threats from North Korea. The week-long Hoguk exercise beginning October 25 will involve 240,000 army, navy, air force and marine corps personnel, with 500 US soldiers also taking part. Some 28,500 US military personnel are stationed in the South - a legacy of the Korean War that ended with a ceasefire but not a peace treaty, leaving the two Koreas still technically at war.