The Biden administration sued Arizona Gov. Doug Ducey (R) on Wednesday over his construction of a barrier made of double-stacked shipping containers along parts of the U.S.-Mexico border.

Why it matters: Ducey launched the effort to fill in gaps in the Trump administration's border wall amid a sustained surge in border crossings and has continued the project as a final act before he leaves office in January. Federal authorities have said, however, that the barrier is unlawful since it is erected on U.S. land.

Driving the news: The new lawsuit asks the court to order Arizona to stop building the barrier and remove the containers in the San Rafael Valley, citing operational and environmental concerns. Arizona "is trespassing on federal lands," the complaint states.

• "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 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."
• Arizona's installation has also "detrimentally impacted" law enforcement functions 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."
• The Biden administration is seeking compensation to fix any damages along the border.

What they're saying: Ducey told federal officials earlier this week that the state would help remove the containers, but pushed the federal government to publicly commit to a timeline for permanently filling in remaining gaps in the wall, AP reports.

• He claims he had no other choice but to secure the border himself since the Biden administration failed to do so. His other border security efforts have involved busing migrants to Democratic-led cities.

Worth noting: In recent days, environmental activists have also escalated protests against the construction and held up work on the $95 million project, per AP.

What to watch: Gov.-elect Katie Hobbs (D) has long opposed the barrier and said last week that she is exploring "all the options" for removing the containers.