Roughly 15 years in the making, a multilateral agreement on the planned Turkmenistan-Afghanistan-Pakistan-India natural gas pipeline was signed during meetings in Ashgabat, the capital of Turkmenistan.

Members of a pipeline consortium planning the gas pipeline east from Turkmenistan announced their preliminary shareholder arrangements at a steering committee.

Sean O'Sullivan, director general for the region at the Asian Development Bank, which supports the project, said the momentum was a welcome milestone for the project.

"ADB looks forward to the stakeholders continuing to build on the strong momentum in the implementation of the TAPI pipeline project," he said in a statement.

Project leaders include Turkmengaz, the consortium leader and state-run gas company of Turkmenistan, and Indian energy company GAIL. Turkmengaz was named as the pipeline's consortium leader in August.

Turkmenistan is expected to send up to 1.1 trillion cubic feet of natural gas per year to Afghanistan, Pakistan and India for the next 30 years once the pipeline is completed. The pipeline, described as part of the "new Silk Road," is favored by the United States and its allies over the similar, but long delayed, natural gas pipeline stretching east from Iran.

The project is described as essential for regional economic and energy developments. It would draw on the Galkynysh natural gas field near the border of Afghanistan, one of the largest gas fields in the world, with an estimated 925 trillion cubic feet of reserves. TAPI has drawn Western interest in a region where adversaries Iran and Russia play a dominant energy role.

ADB took a lead role in the project in 2003. It was appointed as the transaction adviser for the pipeline in 2013.