Washington — Responding to concerns raised by Democratic lawmakers, Congress' independent watchdog will launch an investigation into the administration's intensifying efforts to seize private land to build barriers along the U.S.-Mexico border and fulfill one of President Trump's signature campaign pledges.

The Government Accountability Office notified Democratic leadership in the Senate that it will review the Trump administration's attempts to take over private property near the southern border through eminent domain, a power the government has to expropriate land for public use as long as the landowners are compensated. Many landowners oppose these efforts and are taking the administration to court in a bid to keep their property.

In its notification to Senate Minority Leader Chuck Schumer, dated September 5 and obtained by CBS News, the Government Accountability Office said the matter was within its purview to investigate. The office said it would consult with the Department Homeland Security's inspector general to make sure it is not duplicating investigations.

Workers break ground on new border wall construction about 20 miles west of Santa Teresa, New Mexico, on Aug. 23, 2019. The wall visible on the left was built in 2018 with money allocated by Congress, while the new construction is funded by money reallocated from Department of Defense funding. AP

Democrats, who have long opposed Mr. Trump's efforts to build a border wall, praised the move.

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"Make no mistake: this administration is trying to take away Americans' private property without an ounce of oversight and has repeatedly failed to provide basic, critical information, including how many citizens will have their land seized," Schumer wrote in a statement Wednesday.

Frustrated with the scant information from the administration on its use of eminent domain, Schumer and fellow Democratic Senators Dick Durbin, Tom Udall and Martin Heinrich had asked the Government Accountability Office last month to initiate an inquiry. They asked the office to look into the number of citizens who could potentially have their land seized, the cost the property acquisitions, the time it will take and the administration's work to compensate landowners.

Durbin applauded the investigation into what he called Mr. Trump's "land grab," saying in a statement that private lands along the border belong to local residents, not to the federal government. Udall, who represents the border state of New Mexico, went further, calling on the administration to stop invoking eminent domain until the Government Accountability Office concludes its probe.

"Under this administration's thoughtless and potentially lawless land grab, homes could be confiscated, farms and livelihoods ruined, neighbors cut off from one another, Tribal sovereignty upended, and endangered species and habitat lost forever," Udall said in a statement.

The federal watchdog's decision comes as the president rushes to deliver on his vow to build a wall to deter illegal border crossings, which have dropped in recent months since a 13-year monthly high in May. Mr. Trump has often embraced eminent domain, calling it "necessary" to bolster border security.

With a little over a year left until the 2020 presidential election, the president has been urging officials to ramp up efforts to build new barriers or replace dilapidated ones in both public and private lands near the southern border as quickly as possible. Along with other promises to crackdown on illegal immigration, Mr. Trump's vow to erect a wall along the border with Mexico galvanized his supporters in 2016, and he's hoping construction will energize his base for his reelection.

After a two-month-long impasse with congressional Democrats that led to the longest government shutdown in U.S. history, Mr. Trump declared a national emergency over immigration in February and indicated he would take unilateral action to secure funding for his long-promised border wall.

The Pentagon has already signed off on two controversial multi-billion-dollar transfers of funding from different parts of its budget to be used to finance the construction of border barriers.