The Trump administration has begun building the border wall through a west Texas section of the Big Bend region.

This is the first major construction in an area where its plans have faced heavy opposition.

It marks a milestone in the administration’s $46 billion plan to line the border with walls, barriers, roads and technology.

President Donald Trump promised to finish the wall as a key campaign promise.

Customs and Border Protection said border wall panel installation is underway in a 47-mile stretch of Hudspeth County known as Big Bend 1.

The agency said the first panels were erected on September 15.

A photo showed a crane lifting one of the 30-foot tall steel panels into place.

This work is separate from a project in nearby Big Bend National Park, where construction has been temporarily suspended.

In the wider Big Bend region, CBP has faced opposition from landowners, environmental groups, business owners and ranchers.

They say the remote region is not a high traffic area for illegal immigration.

Clara Benson, a founder of the No Big Bend Wall Coalition, said the group would keep fighting the plans.

She said the fight is not over.

CBP said it is building an average of 12 miles of barriers a week across the 2,000-mile border with Mexico.

The agency said it recently hit 200 miles of new barriers since the second Trump administration took office.

That pace is double what agency head Rodney Scott cited earlier this year.

The agency has also faced opposition from environmental groups, a small town worried about flooding, Native Americans and landowners.