A singer from China's Tibet Autonomous Region performs during a concert in Ulan Bator, Mongolia, Sept. 16, 2019. A concert celebrating Mongolia's longtime friendship with China was staged in the capital city on Monday evening. (Photo: Suriya/Xinhua)

Artists from China's Tibet Autonomous Region perform during a concert in Ulan Bator, Mongolia, Sept. 16, 2019. A concert celebrating Mongolia's longtime friendship with China was staged in the capital city on Monday evening. (Photo: Suriya/Xinhua)