LAS VEGAS -- A spike in copper thefts from Nevada electrical substations has prompted federal officials to warn about safety and the possibility of power outages.

The Western Area Power Administration issued a plea for public help, while posting a reward for information in recent break-ins.

"It's amazing what people will do," administration spokeswoman Carolyn Hinkley said, citing the arrest of two men July 22 after officials said they tried to remove copper wire from the high-voltage Mead substation near Boulder City.

It was the only arrest after nine break-ins at the substation in a little more than a year. Hinkley attributed the thefts to rising copper prices.

From 2001 to 2005, there were four break-ins at federally owned substations in Nevada, officials said. Since April 2006, there have been 13.

Nevada Power Co. and Valley Electric Association, which serves portions of Nye, Clark, Esmeralda and Mineral counties, have also reported a surge in recent copper thefts.

At the scene of a January break-in at a VEA substation near Sandy Valley, southeast of Las Vegas, blood was found on gloves and some electrical equipment, leading investigators to believe a copper thief may have been seriously hurt.

Valley Electric announced a $10,000 reward in connection with thefts and vandalism at its facilities.

The Western Area Power Administration offers up to $1,000 for information leading to prosecutions in break-ins.

Marketing Director Staci Behnke said the reward has so far failed to elicit information that would lead to the arrest and conviction of a suspect or suspects.

"We have people come forward, they think they've seen something," she said. Law enforcement is notified and asked to inspect the cited area, "but nothing has come to fruition.

Behnke said the theft problem has been low key in the Pahrump area, at least for the time being, but the same cannot be said elsewhere in the Southwest and, for that matter, in the nation as a whole.

"There's not too much going on out here," she said, "but it's just crazy everywhere else."

The association delivers hydroelectric power from Hoover Dam and other federal facilities to California, Nevada and other states. It is part of a grid of 17,000 miles of transmission lines across 15 states, including almost 200 miles of power lines and five substations in Nevada.