LINCOLN, Neb. — The developer of the Keystone XL oil pipeline made good on its promise Tuesday to try to seize access to the Nebraska land it needs to finish the project — the first steps it's taken since the state's high court removed a major legal barrier.

TransCanada employees said the company filed legal papers in nine Nebraska counties to invoke eminent domain for the land that's needed to construct, operate and maintain the pipeline. The filings come just before the company's two-year window closes Thursday.

The pipeline still faces legal challenges in Nebraska, even though the state's Supreme Court allowed the route to stand by default. Opponents have sued to try to prevent the Calgary, Alberta-based company from using eminent domain and to overturn the state pipeline-siting law that allowed ex-Gov. Dave Heineman to approve the route in 2013.

The pipeline would carry an estimated 800,000 barrels of crude oil a day to Nebraska, where it would connect with existing pipelines headed for Gulf Coast refineries.

By law, TransCanada can use the courts to force Nebraska landowners to sell access to their land. Company officials say they still need to acquire 12 percent of the total land easements from owners who have not yet reached a deal. Some holdouts have said they won't negotiate no matter how much TransCanada offers.

The company has acquired 100 percent of the private landowner easements in Montana and South Dakota, according to TransCanada's Keystone projects land manager Andrew Craig.

"This is all we have left," Craig told The Associated Press. "... We think 88 percent voluntarily agreements in the last two years is a substantial success."

Pipeline opponents argue that many of the landowners in Montana and South Dakota were "bullied" early in the process and told they had no other option.

Craig said the company has secured voluntary agreements with as many as 96 percent of the landowners in some of the remaining Nebraska counties. And he expects the company will sign agreements with at least half of the remaining landowners without having to use eminent domain.

Those still willing to negotiate mostly have concerns about compensation and restoration of native grasslands that could take three to five years to regrow, Craig said.

Jim Tarnick has received at least six offers — ranging from $30,000 to $58,000 — for his land on the route just south of Fullerton. TransCanada also sent the 39-year-old a letter and tried to call him last week after the court's ruling.

He opposes the pipeline and plans to continue fighting it, though he isn't part of the new lawsuits.

"If we can't stop the project, we at least have to do what's best for us and future generations," said Tarnick, who is concerned about the pipeline's possible effects on groundwater and soil. "When they're done with it, we're going to be left with a pipe in the ground."

Environmentalists and other pipeline opponents argue that any leaks could contaminate water sources and the project would increase air pollution around refineries and harm wildlife. Supporters, including state and national Republicans and oil industry members, say those fears are exaggerated and argue that the pipeline would create jobs and ease the country's dependence on foreign oil.

President Barack Obama has downplayed the project's benefits, and the White House has publicly threatened to veto legislation in Congress that would fast-track the project.

Nebraska lawmakers may debate the issue again this session. State Sen. Ernie Chambers introduced a bill Tuesday that would repeal the pipeline-siting law and bring the project "to a virtual standstill."

"The pipeline is like King Kong, and the people and farms are like ants and grasshoppers," Chambers said. "If they get in the way, they will be crushed with no redress."

It's not clear how it'll be received in the Legislature.

In the two lawsuits filed last week — which could delay the entire 1,179-mile Canada-to-Nebraska project — seven landowners in Holt and York counties said they've received written warning that TransCanada intends to initiate eminent domain proceedings.

Associated Press writer Anna Gronewold contributed to this report.