Construction has begun on the Afghan section of a major gas pipeline linking four countries in Asia.

The project is backed by the US, Pakistan and even the Taliban, as it is hoped transit fees will help stabalise Afghanistan's economy.

The project, known as TAPI, the initials of the four countries, is being described as a new page in regional co-operation.

The pipeline will run 1814km, will carry 33 billion cubic metres of natural gas each year, and is expected to be completed by January 2020.

Al Jazeera's Imtiaz Tyab reports.