Donald Trump has issued a new permit for the controversial Keystone XL pipeline.

The move aims to speed up the development of the pipeline, which is designed to be able to transport 800,000 barrels a day of crude oil from tar sands in Alberta, Canada to the US Gulf Coast.

It was first proposed in 2008 under President George W. Bush and rejected by former President Barack Obama in 2015.

President Trump reversed that decision again in 2017 and says his new permit replaces the previous one granted two years ago.

The move comes despite a federal judge blocking the project at the end of last year due to the risk of potential oil spills and other impacts.

Critics of the project say the pipeline and related oil-infrastructure will harm indigenous communities, contribute to climate change and damage the environment.

Mr Trump said: “By virtue of the authority vested in me as President of the United States of America, I hereby grant permission, subject to the conditions herein set forth, to TransCanada Keystone Pipeline, L.P. (hereinafter referred to as the “permittee”), to construct, connect, operate and maintain pipeline facilities at the international border of the US and Canada at Phillips County, Montana, for the import of oil from Canada to the US.

“This permit supersedes the Presidential permit issued to the permittee, dated March 23, 2017. For the avoidance of doubt, I hereby revoke that March 23, 2017, permit.”