Environmental groups plan to sue the Trump administration over offshore drilling tests, launching a legal fight against a proposal that has drawn bipartisan opposition along the Atlantic Coast, two people with direct knowledge of the pending litigation told The Associated Press.

The lawsuit, which aims to stop the issuance of permits for the use of seismic air guns, will be filed by a coalition of environmental groups in federal court in South Carolina on Tuesday, according to the individuals. They spoke on condition of anonymity because they were not authorized to speak publicly before the suit is filed.

The Trump administration has authorized five such permits, which aim to find oil and gas formations deeply below the Atlantic Ocean floor, from Delaware to central Florida, an area where seismic surveys haven't been conducted in decades.

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The blasts are conducted in preparation for potential offshore drilling, which the administration has proposed to expand from the Atlantic to the Arctic and Pacific oceans. The five-year plan would open 90 percent of the nation's offshore reserves to private development.

Survey vessels will be required to have observers on board to listen and watch for marine life and alert operators if a protected species comes within a certain distance, officials have said, and acoustic monitoring will be used to detect those animals swimming beneath the ocean surface. Surveys would be shut down when certain sensitive species or groups are observed and penalties could be imposed for vessels that strike marine animals.

The precautions aren't enough for environmental groups, who have said the blasts can disturb marine mammals. Industry groups say the surveys have been conducted around the world for decades, with little adverse impact.

The drilling issue has created strange political bedfellows along the East Coast, with Democrats and Republicans in some areas united over the issue. In South Carolina's 1st Congressional District, Republican Katie Arrington — a supporter of President Donald Trump who initially said she stood by his plans to open up Atlantic Coast drilling — later backed off that support amid a growing wave of drilling opposition in the coastal district she aimed to represent.

Arrington ultimately lost the general election to Joe Cunningham, a Democrat staunchly opposed to drilling who collected support from coastal Republican mayors. Voters said they had been turned off by what they saw as Arrington's flip-flop on the issue, and they turned instead to Cunningham's consistency.

On Monday, Cunningham told the AP that he backed the legal effort, which would pair with legislative action he plans to take up in the U.S. House.

"I'm going to go up to D.C. and fight like hell," Cunningham said. "These lawsuits are one tool in our bag that we're going to use."

South Carolina Gov. Henry McMaster's early support of Trump's candidacy hasn't stopped him from opposing the president's drilling plans. Earlier this year, McMaster was among state executives to request a drilling waiver, seeking the same sort of promise already given to Florida Gov. Rick Scott, another Trump ally. Since then, officials from the Department of the Interior have said Secretary Ryan Zinke's promise to Florida was not a formal action and will instead be part of the department's analysis as it completes its plans.

In February, McMaster met with Zinke at the Governor's Mansion in Columbia. This week, McMaster spokesman Brian Symmes told The Associated Press that the governor and the state's top prosecutor, both Republicans, would continue to work on a plan to keep drilling away from the state.

"The governor and Attorney General (Alan) Wilson have resolved to continue working together to determine the best path forward," Symmes said. "Anything and everything is on the table to keep us from seeing seismic testing or offshore drilling off the coast of South Carolina."

State Rep. Nancy Mace, a Republican representing parts of the greater Charleston area, supports the lawsuit, which she called South Carolina's best option to challenge federal government overreach.

"The government doesn't get to pick winners and losers in this thing," Mace said. "When you have every mayor, every community saying, 'We don't want this,' and now you're going to shove seismic testing down our throats? I don't think so."

Mace said she is concerned both with potential environmental damage and the possible threat to South Carolina's $20 billion tourism industry, much of which centers around the coast.

"We have the potential to destroy that beauty off our coast with rigs that nobody wants," Mace said. "We've got to do something, and a lawsuit might be the only way to do it."