HOUSTON (AP) — Top Trump administration officials visited Texas five days before Election Day to announce they have nearly completed 400 miles of U.S.-Mexico border wall, trying to show progress on perhaps the president's best-known campaign promise four years ago.

While most of the wall went up in areas that had smaller barriers, the government built hundreds of miles of fencing as high as 30 feet (9 meters) in a short amount of time — most of it this year. But crews blasted hills and bulldozed sensitive habitats in national wildlife refuges and on American Indian land to do it, prioritizing areas where they could build more quickly.

The Department of Homeland Security waived environmental and other reviews to expedite construction. And despite President Donald Trump's repeated promises that Mexico would pay for the wall, the construction has been funded by U.S. taxpayers for at least $15 billion, two-thirds coming from military funding.

In Texas' Rio Grande Valley, where Acting Homeland Security Secretary Chad Wolf and other officials spoke Thursday, authorities have added just 7 miles (11 kilometers) to sections of stop-and-start fencing. That's despite the region long being the busiest corridor for unauthorized crossings.

DHS officials have held several events announcing immigration operations this month in states considered competitive in the election. Polls show a tight race in Texas, which has not supported a Democrat for president since 1976. Stephen Miller, a top Trump adviser, told reporters Wednesday that “we have a president campaigning on having successfully built a border wall.”

Wolf and other officials echoed Trump's campaign attacks Thursday at an official government event. Wolf criticized House Speaker Nancy Pelosi, judges who have ruled against the wall and what he labeled “outright lies in the press.” Mark Morgan, acting commissioner of U.S. Customs and Border Protection, claimed that he was locked out of his Twitter account for posting support for the wall and alleged without evidence that rolling back Trump's immigration programs would lead to an “invasion” of immigrants.

“The wall system we're looking at right now, it works,” Morgan said.

Laiken Jordahl, a field campaigner for the Center for Biological Diversity Action Fund, has documented the destruction of sensitive areas along the border.

“We’re seeing this administration just blow up anything in their path in order to build an additional mile of wall,” he said. “None of this is about border security. It’s about inflating this mile count in order to make Trump look tough for reelection.”

Border Patrol Deputy Chief Raul Ortiz said this week that the agency was not pushing to build quickly this year in case Trump loses to Democrat Joe Biden, who has pledged to freeze any border wall construction if he wins.

“For us, regardless of who’s sitting in the White House, I think giving the agents the tools and the resources are going to be awfully important," Ortiz said. “This infrastructure is important to us doing everything we can to control that border."

Border Patrol officials say the new fencing, much of which has replaced much smaller vehicle barriers, provides more deterrence against human smugglers and people trying to elude capture. The construction also includes roads, lighting and cameras that help agents detect illegal activity.

Wolf claimed the new sections allowed agents to push border traffic into areas they could better control. But the Government Accountability Office has found that CBP couldn't demonstrate how existing border walls improved security. Most drugs are smuggled through ports of entry, not across unfenced areas.

The Trump administration has enacted other measures to stop border-crossers, including new restrictions on asylum eligibility and a public-health declaration citing the coronavirus pandemic that allows agents to quickly expel most migrants.

As of last week, 381 miles (613 kilometers) of wall have been completed during the Trump administration. More than 270 miles (435 kilometers) were built using part of the $10 billion that Trump took from military funding under a national emergency he declared last year after Congress refused to meet his request for wall funding.

Congress has funded about $5 billion for border barriers under Trump, including more than $3 billion in the last two fiscal years for construction in the Rio Grande Valley and around Laredo, Texas. Of the more than 150 miles (241 kilometers) funded by Congress in the last two years, just 5 miles (8 kilometers) have been built.

The government faces significant obstacles in Texas, where the border is formed by the Rio Grande and the river floodplain is governed by international treaties. Much of the land is privately owned. While government attorneys have filed dozens of condemnation lawsuits this year, many landowners have refused to allow agents onto their land or surrender property without a court order.

“We’re still fighting it,” said Lilly Cavazos Rodriguez, whose family owns land in South Texas that the government has gone to court to seize. The family is being represented by the nonprofit Texas Civil Rights Project, which has organized landowners to fight the government in court.

“We’re not willing to give up our land, so we’re going to fight as long as we can," she said.