North Korea is unlikely to respond to calls from South Korea for a joint investigation into an alleged drone incursion, analysts said, dimming hopes in Seoul that the incident could help break a deadlock in inter-Korean relations. Pyongyang has accused South Korea of sending drones into its territory on two occasions — once in September last year and again on Jan. 4 — claims Seoul's military immediately denied. South Korean officials said they will continue efforts to de-escalate tensions on the Korean Peninsula. On Monday, South Korea's police and military launched a joint task force of about 30 members to investigate the incident. The move came two days after President Lee Jae Myung ordered a swift probe, warning that any drone flights carried out by civilians pose a serious threat to national security. South Korea's defense ministry said a joint probe with the North has not been formally proposed to Pyongyang, but remains a possible option depending on the outcome of the ongoing police investigation. "The facts need to be clarified through the investigation before we can review ou