Leaders from Afghanistan, India and Pakistan have joined the president of Turkmenistan in breaking ground on a new pipeline intended to deliver natural gas from the energy-rich former Soviet republic to their three countries.

Turkmenistan is believed to have the world's fourth-largest gas reserves, but currently exports mainly to China.

Turkmen President Gurbanguly Berdymukhamedov was joined at Sunday's ceremony by the Afghan president, Indian vice president and Pakistani prime minister.

India's Hamid Ansari said the launch of the pipeline "marks the first step toward fulfilling the vision of an economically integrated region stretching from the Bay of Bengal to the Caspian Sea."

The 1,800-kilometer (1,080-mile) TAPI pipeline is intended to carry gas through the Afghan cities of Herat and Kandahar and end up in the India-Pakistan border town of Fazilka.