The federal government sued Monday to gain access to land owned by a Texas city whose mayor has been highly critical of a planned U.S.-Mexico border fence.

The lawsuit against Eagle Pass, Texas, is the first of scores expected to be filed in the escalating dispute. The Homeland Security Department has said it needs access to land to find the best places to build the fence or to set up other border security.

Eagle Pass Mayor Chad Foster serves as chairman of the Texas Border Coalition, a group of border mayors, business officials and residents.

"We ain't rolling over," Foster said after learning of the lawsuit.

The Homeland Security Department is trying to build 370 miles of border fence by the end of the year. A 2006 law signed by President Bush and supported by both of Texas' U.S. senators mandated a total of 700 miles of fence along the border.

Coalition members allege that the agency has failed to sufficiently consider concerns about effects on the environment, residents' property and the binational way of life along the border and has ignored suggestions for alternatives.

"Interior members of the U.S. think this is something new. The Texas border has been fighting illegal activity on the border for generations," Foster said. "As we speak today we have camera towers on the river, sensors on the river and border patrols patrolling the river."

Last month the Homeland Security Department warned landowners in Texas, California and New Mexico that it would sue if it was not given access to their property. Some have granted access, but several have ignored the warning.

"We have been and continue to be absolutely clear about our commitment to border security," said Laura Keehner, a Homeland Security spokeswoman.