The relocation of US forces away from 26 military bases in South Korea, including facilities in the capital and close to the border with North Korea, could lead to an improvement in relations between Beijing and Seoul, analysts said.
Since the end of the Korean war in 1953, the United States has held "wartime operational control" over not only its own forces in the country - which number about 28,500 - but also South Korean troops. While there is no plan for US forces to leave the country, their departure from key locations could pave the way for further discussions on the return of wartime control to Seoul, a move that would be welcomed by Beijing.
"If South Korea regains control, it would ease the confrontational atmosphere on the peninsula, which would be good for China," said Yue Gang, a retired colonel from the People's Liberation Army, China's military.
The plan to relocate American troops was drawn up in the early 2000s but has suffered repeated setbacks. However, after coming under pressure from its host to speed up the process, the US said this week it was committed to returning the bases to Seoul "as expeditiously as possible".
In a statement released on Wednesday, US Forces Korea (USFK) said 15 of the 26 installations had been vacated and closed, and were now available for transfer to the South Korean government.
"The perception is that USFK is holding up the process when the reality is we've already got 15 of 26 bases and five parcels of Yongsan that are ready to be turned over to the (South Korean) government," USFK spokesman Colonel Lee was quoted as saying by US military newspaper Stars and Stripes.
The announcement came ahead of planned talks between defence officials from the US and South Korea in Seoul next week, and amid growing concerns of a rift between the long-time allies.
China, meanwhile, has held long-term concerns about the presence of US troops in South Korea. Tensions escalated in 2016 after Seoul agreed to host the US military's THAAD (Terminal High Altitude Area Defence) missile system.
Beijing responded by banning Chinese tour groups from visiting South Korea and refused entry to its neighbour's pop stars.
While the relocation of US forces away from certain military bases may ease some of the tension between the two countries, Liu Weidong, a US affairs expert at the Chinese Academy of Social Sciences, said the move was more to do with Seoul's relationship with Washington than with Beijing.
"Ties between the two countries (US and South Korea) may be under pressure - the handover of the US bases was mainly a result of the strong nationalistic sentiment in South Korea - (but) South Korea is still the US's military ally in the region. Its ties with the US are more cohesive than with China," he said.
Since the Korean war ended in a ceasefire, the aim of the US troops stationed in South Korea has been to defend its ally while also keeping China and Russia in check.
While discussions about the relocation of those forces have been going on for a decade, the process accelerated last year amid signs of warmer ties between the two Koreas, aided by three summits between South Korean President Moon Jae-in and North Korean leader Kim Jong-un, as well as Kim's historic meetings with US President Donald Trump.
Yue said Pyongyang was likely to welcome the changes.
"North Korea has been upset about the military drills between South Korea and the US, but if Seoul is in charge it might reduce the scale of the exercises or remove sensitive elements to avoid provoking its neighbour."
There has also been speculation that Moon is keen to use the move to shore up his flagging approval ratings.
But Song Zhongping, a Hong Kong-based military commentator with Phoenix TV, said that South Korea might not yet be ready to completely replace the US, especially as progress in the negotiations on the denuclearisation of the peninsula had yet to make much progress.
"South Korea needs to assess if it can take over more responsibility and if Moon's 'sunshine (reconciliation) policy' on North Korea can really translate into practice."
Additional reporting by Kristin Huang
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