SEOUL — Vowing strong retaliation, South Korea said on Monday that North Korean soldiers laid the three mines that exploded last week at the heavily fortified border, maiming two South Korean soldiers. South Korea's military, which investigated the mines, said that Pyongyang will face unspecified “searing” consequences for the mine blasts in the Seoul-controlled southern part of the Demilitarized Zone that has bisected the Korean Peninsula since the end of the Korean War in 1953. The US-led UN Command, which also conducted an investigation that blamed Pyongyang for the mines, condemned what it called violations of the armistice that ended fighting in the Korean War, which still technically continues because the participants have yet to settle a peace treaty. The soldiers were on a routine patrol near a wire fence in the southern side of world's most heavily armed border when the explosions happened. One of the soldiers lost both legs, while the other lost one leg. More than a million mines are believed to be buried inside the DMZ, and North Korean mines have occasionally washed down a swollen river into the South, killing or injuring civilians. But North Korean soldiers crossing the border and planting mines is highly unusual. The explosions come amid continuing bad feelings between the rival Koreas over the establishment of a UN office in Seoul tasked with investigating the North's alleged abysmal human rights conditions. Pyongyang also refuses to release several South Koreans detained in the North. Things are expected to get worse next week when Seoul and Washington launch annual summertime military drills, which the allies say are routine but that Pyongyang calls an invasion rehearsal. Seoul's announcement on the mines will likely trigger a furious response from Pyongyang, which has denied a slew of previous provocations that South Korea has blamed on North Korea. The North typically calls the South's statements attempts to create anti-Pyongyang sentiments in Seoul. In 2010, a Seoul-led international investigation blamed Pyongyang for torpedoing a warship and killing 46 South Korean sailors. The North denies responsibility. It's unclear what retaliatory measures Seoul might take for the mine explosion. Military strikes are unlikely, as the North has placed a huge portion of its artillery within striking distance of the South Korean capital of Seoul. South Korean sanctions imposed after the 2010 warship sinking are a source of tension between the rivals. Critics say the measures have also hurt South Korean businessmen who had earlier dealings with North Korea. Investigations by South Korea and the American-led UN Command showed that splinters from the explosions were from wood box mines used by North Korea, according to South Korea's Defense Ministry. South Korean officials say there's no chance that old mines had dislodged and drifted to the South because of rain or shifting soil. The area where the soldiers were patrolling is on higher ground than the places where North Korean mines have been previously planted, meaning the recent mines must have been purposely laid there by the North, chief South Korean investigator Ahn Young-ho told reporters. A senior South Korean military officer, Ku Hongmo, said that Seoul believes North Korean soldiers secretly crossed the border and laid mines between July 23 and Aug. 3, the day before the three mines exploded. But he said that surveillance cameras in the area did not detect any suspicious North Korean activities, apparently because of bad weather and forest cover. A border line runs through the middle of the 4-kilometer (2.5-mile-wide) DMZ, which is jointly overseen by the UN Command and North Korea. South Korean troops patrol the southern part of the buffer zone, according to Seoul's Defense Ministry. — AP