Donald Trump and other supporters of the Keystone XL pipeline tout it as a major source of jobs.

"If we can get that pipeline built. A lot of jobs; 28,000 jobs. Great construction jobs," he said when signing executive orders this week aimed at restarting both Keystone and the Dakota Access pipelines that the Obama administration had blocked.

But according to official estimates, constructing the pipeline will generate far fewer construction jobs than that.

A State Department report on the pipeline that was issued under the Obama administration found that there would be 3,900 direct construction jobs if it was built over one year, or 1,950 if the work was spread over two years.

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Once the pipeline opens it would require only 35 full-time permanent jobs to run it, and 15 full-time temporary jobs, according to the state department report. TransCanada, the company seeking to build the pipeline, does not dispute those numbers.

The company and other supporters argue that the pipeline would create jobs indirectly for companies that sell products and services used to build the pipeline. The State Department report estimates that there would be a total of 42,000 indirect jobs created, with a total of $2 billion in wages. That comes to an average of about about $47,000 in wages per job.

TransCanada also pointed out that there would be benefits beyond the jobs and wages, including "significant property tax revenues, as well as sales and use and other tax revenues, to counties and states along the proposed project route."

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Trump insisted that his administration will demand that the pipeline is built with only U.S.-made pipe, further boosting American jobs.

"I am very insistent that if we are going to build pipelines in the United States, the pipes should be made in the United States," he said.

But the order only specifies that U.S. made pipe being required "to the maximum extent possible and to the extent permitted by law."

TransCanada did not commit to using U.S.-made pipe on the project.

"We are aware that the Secretary of Commerce will come up with a plan to implement the executive order," said TransCanada spokesperson Terry Cunha. "We will need time to review and analyze the plan when it is released to determine its impact to Keystone XL."