India, Sept. 23 -- China on Tuesday spelt out Taiwan as a "red line", a day ahead of President Xi Jinping's visit to Washington for a summit with his US counterpart Donald Trump. Beijing claims Taiwan as part of its mainland. Xi's meeting with Trump on Thursday during his three-day visit to Washington will be the two leaders' second meeting since May. Announcing Xi's visit, the Chinese Foreign Ministry said on Monday that the leaders' meeting within a span of half a year marks a "milestone of historic significance". During the meeting, Xi is widely expected to convey China's firm opposition to America's proposed $11 billion arms package for Taiwan, which Trump has yet to approve and urge the US leader to scale down Washington's support fo...