Vietnam on Thursday called for the “immediate withdrawal” of a Chinese ship in the South China Sea, as the standoff over the disputed waters intensified. Beijing last week issued a new call for Hanoi to respect its claims to the resource-rich region — which have historically been contested by Vietnam as well as Taiwan, the Philippines, Malaysia and Brunei. Hanoi responded by saying it had sent several messages to Beijing insisting that a Chinese survey ship vacate its waters, and doubled down Thursday with new demands for the vessel’s removal.