The US government has sued Republican governor Doug Ducey and the state of Arizona for building a wall with shipping containers along parts of the US-Mexico border.
The Department of Justice filed the lawsuit in the US District Court to seek an order to halt the placement of the barriers and remover containers from the remote San Rafael Valley in easternmost Cochise County.
The complaint filed on Wednesday cited operational and environmental concerns, adding that Arizona “is trespassing on federal lands”.
The latest move by the Biden administration comes amid a high-profile standoff between the Arizona governor and the federal government.
In just three weeks the Republican governor is set to step aside for incoming Democratic governor-elect Katie Hobbs, who has said she opposes the construction.
Mr Ducey’s efforts to erect a wall with hundreds of double-stacked shipping containers began in late summer in Yuma in western Arizona, a popular crossing point, with scores of asylum-seekers arriving daily. He said wanted to “secure” the border, filling gaps in the Trump administration’s border wall.
The work to stack up to 3,00 containers, costing $95m is about a third complete.
Its progress was recently slowed down by protests from environmental groups, who have raised concerns over environmental damages to native species and natural water systems in the region.
“In installing shipping containers on National Forest System lands, Arizona has widened roads and cleared lands for staging areas ... cut down or removed scores of trees, clogged drainages, and degraded the habitat of species listed under the Endangered Species Act,” the complaint stated.
“The shipping containers are blocking approximately thirty naturally occurring ephemeral watercourses, which will interrupt natural watershed patterns, erode soil in the immediate area, and damage vegetation and forage.”
It added that the installation of the wall also “detrimentally impacted” law enforcement work and “interfered with the Forest Service’s ability to carry out its official duties by, among other things, causing the National Forest System lands to be occupied by armed private security guards”.
DoJ is seeking damages to compensate the US to fix any damage along the border.
Following resistance, Mr Ducey said earlier this week that Arizona will help the federal government in removing the containers, which he said were a temporary barrier.
But he demanded the US government fill the remaining gaps in the permanent border wall as it announced it would a year ago.
In a letter on Tuesday, he wrote that the US "owes it to Arizonans and all Americans to release a timeline”.
He wrote to the federal officials after he was informed of the pending complaint and pushed back against their argument that containers “present serious public safety risks and environmental harms”.
"The number one public safety risk and environmental harm has come from inaction by the federal government to secure our border," Mr Ducey wrote.
He added that halting the construction of Donald Trump's border wall resulted in "an ever-increasing number of migrants who continue to flow into the state”.
His move to stop migrants crossing the border comes amid a record influx of asylum seekers. Border officials have thwarted migrants’ efforts to cross the border more than 2.28 million times in the fiscal year ending 30 September.