Secretary of State Rex Tillerson is directing USA diplomatic missions to identify "populations warranting increased scrutiny" and to toughen screening for visa applicants in those groups, according to diplomatic cables seen by Reuters.
The 1,200-mile pipeline - which would deliver crude from western Canada to the Gulf Coast - has been the subject of almost a decade of controversy and emphatic lobby efforts by both environmentalists and the oil industry. The White House will then formally announce the final approval.
Tom Shannon, the State Department's undersecretary for political affairs, will sign TransCanada's permit, making good on one of President Donald Trump's campaign promises.
That decision would clear the way for formal approval by the White House.
While the permit will eliminate a crucial barrier for the pipeline, other hurdles still remain, including winning approval for the project in Nebraska and from landowners there who have denied it the right of way. Spokesman Terry Cunha said the company was working closely with the State Department.
The approval follows years of intense debate over the pipeline amid hefty opposition from environmental groups, who argued that the pipeline supports the extraction of crude oil from oil sands, which pumps about 17% more greenhouse gases than standard crude oil extraction.
The Nebraska Public Service Commission also has to approve the pipeline's route; a decision that is expected in late September, according to Politico.
The Obama administration had previously rejected the pipeline.
Because the pipeline crosses an worldwide border, it requires formal approval from the State Department.
In rejecting the pipeline, the Obama administration had argued it would undercut U.S. efforts to clinch a global climate change deal that was reached weeks later in Paris. The company first applied for a permit in 2008. Supporters for the pipeline argue that its construction will create jobs and stimulate the economy.