U.S. President Donald Trump will test his deal-making capabilities on a trip to Asia, a region battered by his hardball trade policies, while doubts hang over his highly anticipated meeting with China's Xi Jinping.

Trump, who left Washington on Friday night, is set for a five-day trip to Malaysia, Japan and South Korea, his first to the region and longest journey abroad since taking office in January.

The Republican leader hopes to pile up trade, critical mineral and ceasefire deals before turning to the toughest challenge, a face-to-face with Xi on Thursday in South Korea.