North Korea drones: South's military apologises for pursuit failure
South Korea's military has apologised for failing to shoot down five drones that North Korea flew across their mutual border on Monday.
Seoul fired warning shots and sent jets and attack helicopters to shoot down the aircraft, one of which flew close to the capital.
Despite a five-hour pursuit, the drones reportedly all returned to North Korea. 
South Korea's President has said that the incident showed the military's readiness was "greatly lacking".
South Korea's Joint Chiefs of Staff, which represents the major branches of its armed services, acknowledged in a statement on Tuesday that while the military can counter "attack drones that pose a real threat", it is limited in its ability to detect and strike smaller spy drones.
"Our military's lack of preparedness has caused a lot of concern to the people," said a senior official, Kang Shin-chul. He added that the military would "actively employ detection devices to spot the enemy's drone from an early stage and aggressively deploy strike assets".
BBC's Seoul correspondent, Jean Mackenzie, has said it is concerning because the drone that flew near Seoul had the potential to run surveillance operations and to photograph sensitive areas.
Speaking at a cabinet meeting on Tuesday, President Yoon Suk-yeol said he would seek to speed up the creation of a military unit to monitor North Korea's military facilities in response to Monday's incident, which would be supplied with cutting-edge stealthy drones.
He also blamed his predecessor, Moon Jae-in, for his "dangerous" North Korea policy that included a 2018 inter-Korean military pact banning hostile activities in the border areas.
Monday's incursion was the first time in five years that North Korean drones had entered the South's airspace and comes amid increased tensions on the peninsula, with the North conducting a record number of missile tests this year.
Local media were reporting that there had been another possible drone sighting in South Korea on Tuesday, but the defence ministry has said that this was a flock of birds.
Earlier this month, the North claimed to have performed major tests needed to help it develop its first spy satellite, which could be used to monitor South Korea. It released an aerial photo of Seoul, which it said had been taken during the test.
Experts believe North Korea is working to refine and improve its weapons, while putting pressure on the United States to ease sanctions in any future negotiations.