By David Lawder and Ben Blanchard WASHINGTON/BEIJING (Reuters) - U.S. President Donald Trump's escalation of a trade war with China left plans in limbo on Monday for high-level negotiations later this week to end the dispute. Stocks around the world tumbled and oil prices hit a one-month low after Trump tweeted on Sunday that he would raise tariffs on $200 billion worth of Chinese goods to 25 percent from 10 percent by the end of the week, and would "soon" target the remaining Chinese imports with tariffs.