LAS VEGAS -- The Bureau of Land Management says it hopes efforts to diffuse a threat to wild horses in the area of the Tonopah Test Range will prevent further wild horse deaths.

Fresh water is being made available and a barrier has been erected to keep the animals from an apparently hazardous pond in an area where 71 or more horses have died since the agency became aware of the problem in late July.

"We don't know yet if the pond is the source of the problem," reported Juan Palma, BLM field manager here. "We suspect it is, though, and having these controls in place is increasing our comfort level about the situation."

A helicopter overflight and ground observations early last Thursday indicate most of the horses have moved away from the pond, and that some have started drinking water from newly placed troughs.

The Air Force and New Mexico-based Sandia Labs are assisting with the BLM effort by hauling water to the animals. The public is not allowed access to the area.

Diagnostic investigations are going on to determine what caused the untimely deaths. Toxicology results are not expected until this week, BLM officials said.

Information about the results will be made available as it is obtained and as other actions may be taken.

The potentially hazardous pond has served as a source of water for more than 20 years, officials said. It is the extreme northwest portion of the herd management area. This area is home for about 250 of the wild horses. They trail throughout the area, and the pond is one of the primary water sources, the BLM reported.

These horses are in a different part of the Nevada Wild Horse Range from the area where BLM conducted an emergency gather earlier in July.

BLM removed 178 wild horses on the eastern edge of the range because of the lack of water. A further gather of from 800 to 850 excess horses is scheduled for December to bring the herd to an appropriate management level of 300 animals.

There are from 1,100 to 1,150 wild horses in the area now, BLM said.