KUALA LUMPUR (Reuters) -Trade talks between the United States and China were moving towards a point where President Donald Trump and President Xi Jinping can have a productive meeting this week, U.S. Trade Representative Jamieson Greer said in Kuala Lumpur on Sunday.    Asked by a reporter if rare earths were discussed at the talks, which started on Saturday, Greer said a broad range of topics were discussed, including extending the truce on trade measures.    "I think that we're getting to a spot where the leaders will have a very productive meeting," he said.    Trump and Xi are expected to meet on Thursday in South Korea, at the end of the U.S. President's five-day trip to Malaysia, Japan and South Korea.    Trump landed in the Malaysian capital on Sunday morning, shortly before Greer spoke, to attend an Association of Southeast Asian Nations summit and witness the signing of a ceasefire deal between Thailand and Cambodia.