The 1,035-kilometer line, which runs through lush tropical mountains and across the Mekong River, will shorten the journey from Kunming to Vientiane to about 10 hours.

"With the opening of the railway, the high mountains are no longer high and the long journeys are no longer long from Kunming to Vientiane," Xi said at the opening ceremony.

He urged both sides to keep up the high standards in the maintenance and operation of the railway, saying that the regions along the railway must be properly developed to ensure the line can benefit people from both nations.