The state of Texas went to court Tuesday to defend placing a string of buoys in the Rio Grande to deter people from crossing the river from Mexico, a day after Gov. Greg Abbott acknowledged moving some of the barriers out of Mexican waters.

The federal government has ordered Texas to remove the barriers and filed suit against the state when Abbott refused.

A study the Justice Department submitted as part of the lawsuit showed that most of the buoys were on the Mexican side of the Rio Grande, where it is called the Río Bravo. It also showed that anchors for the buoys were on the Mexican side.

On Friday, the department said the International Boundary and Water Commission, which regulates the river and settles boundary disputes and issues, saw excavators and workers doing construction in the river and a concrete anchor being repositioned closer to the U.S. bank. The commission had received a call about work going on Thursday night.