Updated

Turkmenistan has begun pumping natural gas from a vast field near the Afghan border that will help it more than double exports to China in coming years.

Chinese President Xi Jinping joined Turkmenistan's president, Gurbanguli Berdymukhamedov, for Wednesday's start of gas production at the South Yolotan field.

Independent British auditor Gaffney, Cline & Associates estimates that South Yolotan may hold up to 21.2 trillion cubic meters (750 trillion cubic feet) of gas, potentially making it the second-largest reserve of gas in the world after the South Pars field, shared between Iran and Qatar.

The former Soviet Central Asian nation is set to boost its gas exports to China to 65 billion cubic meters per year by 2020, up from 25 billion cubic meters this year, according to Turkmen energy officials.