WASHINGTON (Reuters) – President Donald Trump wrote on Twitter over the weekend he would issue a permit for a railway project from Canada’s oil sands to ports in Alaska, a project that has many regulatory hurdles but could help spur shipments of the landlocked crude to foreign markets and U.S. refiners.

“It is my honor to inform you that I will be issuing a Presidential Permit for the A2A Cross-Border rail,” Trump wrote on Twitter. He said his decision was based on the recommendation of fellow Republicans Dan Sullivan, a U.S. senator, and Don Young, a U.S. representative. Projects that cross the U.S. border require presidential permits.

The $17 billion Alaska-Alberta Railway Development Corporation (A2A Rail) project, first proposed in 2015 by Canadian infrastructure financier Sean McCoshen, would move crude from the Alberta oil sands 1,600 miles (2,570 km) to the Alaskan coast, as well as freight in the other direction.

Much of the case for the project has been often-congested pipelines responsible for moving Alberta crude to U.S refineries. However, new pipelines are under construction, reducing the urgency for another transportation option, and European producer BP Plc recently questioned whether global oil demand has already peaked.

Once a permit is issued, A2A would require numerous regulatory clearances in the United States and Canada that would likely take years. The company could not immediately be reached.

Shipping oil by rail has caused several high-profile accidents in both Canada and the United States in recent years, leading to criticism about the practice by some environmental groups.

The White House did not immediately respond to a request for comment on how soon Trump would issue the permit.

The office of Alaska Governor Mike Dunleavy did not immediately respond to a request for comment.

Canadian energy companies have complained that Canada’s regulatory system is too sluggish, and proposed oil pipelines have run into opposition from environmental and indigenous groups in both Canada and the United States.

Trump issued a permit and an executive order in attempts to speed TC Energy Corp’s Keystone XL pipeline project to bring oil sands crude to U.S. refiners, but it has been mired in delays.

(Reporting by Timothy Gardner in Washington and Rod Nickel in Winnipeg; Editing by Matthew Lewis)