A. U.S. congressional think tank has pointed out that the U.S., currently seeking a four-nation forum to counter China, could exclude and marginalize its existing allies such as South Korea.

The U.S. is currently involved in a four-way dialogue, known as the "Quad" that includes Australia, India and Japan, and seeks to develop the forum into a multilateral structure that can keep in check China's increasing influence in the Asia-Pacific region.. 

The U.S. Congressional Research Service(CRS) said in a report on Friday that the Quad may exclude and marginalize the U.S.' traditional bilateral alliances, such as South Korea. 

The CRS said that U.S. ally South Korea is not in the Quad despite fitting the description of being a democracy with maritime interests and growing naval capabilities. 

The report said South Korea appears to be reluctant to be included in a group that antagonizes China, but it may also chafe at exclusion.