Malaysia complains to Vietnam over South China Sea reef expansion, sources say

FILE -In this March 27, 2016, photo, Vietnamese fishermen fix nets on their boat as while docked at Tho Quang port, Danang, Vietnam, after a fishing trip in the South China Sea.

Malaysia has sent a complaint letter to Vietnam over its alleged expansion of a South China Sea reef that both countries claim as their own, two officials told Reuters, in a rare bilateral escalation not involving China.