SEOUL (Reuters) – A last minute flurry of diplomacy aimed at engaging with North Korea ahead of its declared year-end deadline for talks has been met with stony silence from Pyongyang so far, with the looming crisis expected to top the agenda at summits in China next week. FILE PHOTO: A South Korean soldier watches a TV showing a file footage for a news report on North Korea firing a missile that is believed to be launched from a submarine, in Seoul, South Korea, October 2, 2019. REUTERS/Kim Hong-Ji/File Photo The U.S. special envoy for North Korea, Stephen Biegun, was due to leave Beijing on Friday after meeting with Chinese officials. Earlier in the week, Biegun also made stops in Seoul and Tokyo for discussions with counterparts. It is unclear if Biegun had any behind-the-scenes contact with North Korean officials, but his overtures and calls for new talks were not publicly answered by Pyongyang. Biegun’s trip came as China and Russia teamed up this week to propose a resolution that would ease some United Nations Security Council sanctions on North Korea as a way to jumpstart talks. Next week, Chinese, South Korean and Japanese leaders are due to meet in…