US Secretary of Defense Chuck Hagel arrived in Seoul for an unprecedentedly long, four-day visit to the Asian ally that will include annual talks with his counterpart and a visit to the border with North Korea. It is Hagel\'s first trip to South Korea since taking office in February. He is traveling together with Army Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff (JCS). The main purpose of his visit is to hold the annual Security Consultative Meeting (SCM) with South Korean Defense Minister Kim Kwan-jin, where key topics will include Seoul\'s request for a delay in its planned regaining of the wartime operational control (OPCON) of its troops from the US South Korea wants to push back the OPCON transition, slated for December 2015, citing increased threats from North Korea, according to South Korea\'s News Agency (Yonhap). Seoul handed over its operational command to the US-led U.N. troops shortly after the outbreak of the 1950-53 Korean War and regained peacetime OPCON in 1994. But this week\'s talks, set for Wednesday, are not expected to produce any deal on the issue. Other events Hagel plans to attend while in South Korea include a visit on Monday to the demilitarized zone dividing the two Koreas. The trip to the border with North Korea is seen as a symbolic move underscoring the US commitment to South Korea\'s defense. On Tuesday, both Hagel and Dempsey are scheduled to attend a ceremony marking South Korea\'s Armed Forces Day. It would be the first time for the US defense secretary and JCS chairman to attend an Armed Forces Day ceremony in South Korea, a senior defense ministry official said.