ALBUQUERQUE, N.M. (AP) — Almost a half-million acres in southern New Mexico were designated as a national monument two years ago.

Now, members of the state's congressional delegation are pushing for portions of the Organ Mountains-Desert Peaks area to be set aside as wilderness.

While praised by environmentalists, the effort is reigniting the concerns of local law enforcement about their ability to access the area to fight crime.

The legislation introduced by Sens. Tom Udall and Martin Heinrich, both Democrats, would set aside more than 376 square miles — or nearly half of the monument — as wilderness.

The senators say the legislation strikes the right balance between border security and conservation.

"Management changes south of the monument will create additional flexibility for the Border Patrol and improve security at our nation's southern border," Heinrich said in a statement.

The Southwestern Border Sheriffs' Coalition — which represents more than two dozen local sheriff's offices from Texas to California — is reviewing the latest proposal.

Sheriffs along the U.S.-Mexico border say the influence of Mexican drug cartels, human smuggling and illegal immigration are all apparent. They're concerned about jurisdictional issues that prevent them from investigating local crimes that happen within the boundaries of national parks, monuments and federal forests.

Without concurrent jurisdiction, areas can fall prey to smugglers, said Donald Reay, executive director of the Texas Border Sheriff's Coalition, which is part of the larger sheriffs' group. He pointed to problems at Organ Pipe Cactus National Monument in Arizona and Big Bend National Park in Texas.

"On and on, we've had these issues," Reay said. "It's just a continuance and a concern that the sheriffs have over how do we serve the people who are in need from the public safety standpoint when we're not included in the process."

Before the monument was first designated, a series of public meetings led the senators to amend the legislation establishing the monument to include a buffer zone for law enforcement.

U.S. Customs and Border Protection Commissioner R. Gil Kerlikowske wrote in a letter this week that the wilderness proposal would provide a 5-mile buffer between the international border and the area proposed for added protection. Three miles of the zone would allow normal public access, and the other 2 would allow restricted access.

He noted that throughout the buffer zone, his agency would be able to operate motor vehicles, build infrastructure and carry out other activities as it would on any non-wilderness federal land.

Low-level flyovers by the agency and hot pursuits would still be allowed, and the bill includes provisions to allow Customs and Border Protection and other law enforcement personnel access.

Udall said setting aside the wilderness would be the final step in a decade-long process that involved Hispanic leaders, ranchers, sportsmen, utilities, business owners, environmentalists and others.

The senator said the monument has already put Dona Ana County on the map as a tourist destination, and the wilderness designation would attract more visitors.

According to the senators' offices, the town of Mesilla's tax revenues have increased over 20 percent since the monument's creation, and revenue from the lodgers tax in Las Cruces is up, in part, because of conferences and meetings being attracted to the area. New businesses also have opened to offer outdoor recreation opportunities in the region.