(Bloomberg) -- A blaze that left nearly half of Argentina without power was probably sabotage, the government said.

More than 20 million people in the South American nation of 46 million had no electricity for hours on Wednesday evening after a high-tension transmission line outside the Buenos Aires metropolitan area caught fire, shutting off swaths of the grid.

Burn patterns at the scene imply saboteurs set fire to land right beneath the power line, according to a top government official.

“It’s not the type of fire line you see when pastures get burned,” Ricardo Casal, legal secretary to the Economy Ministry, told local news outlets. “Instead, there are precise focal points that, curiously, are under the transmission line.”

The government has asked a judge to investigate.

  • Read more: Millions of Argentines Are in Darkness After Power Line Fire

Electricity was fully restored on Wednesday night, the Energy Secretariat said. A live state tracker of power generation and on-grid demand showed both were back to normal levels on Thursday, though nuclear power plants remained offline.

The fire came amid a heat wave and drought in Argentina, with Buenos Aires enduring its hottest summer in more than a century of record-keeping and the country’s key soybean crop wilting across the Pampas farm belt. 

In the US, grids have seen an unusual uptick of attacks in recent months. As of December, law enforcement agencies were investigating at least eight recent incidents in four states.

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