CARACAS (Reuters) - Venezuela will begin cutting electricity supplies amid a prolonged drought that has limited power generation, the electricity minister said on Thursday, an unpopular measure for a population already struggling to obtain food and medicine.

Electricity Minister Luis Motta speaks during an interview with Reuters at the Guri Dam in Bolivar state, Venezuela April 11, 2016. REUTERS/Carlos Garcia Rawlins

The rationing effort adds to the woes of President Nicolas Maduro, whose socialist administration is facing chronic problems in supplies of staple goods as low oil prices have stretched the OPEC nation’s state-led economic model.

Most of the country’s electricity comes from the massive Guri hydroelectric dam, whose reservoir has reached historic lows as the El Nino weather phenomenon delays the rainy season.

“There will be restrictions,” Electricity Minister Luis Motta said in a televised address, avoiding the use of the politically charged term “rationing.”

“It’s necessary, it’s a sacrifice.”

Power cuts will rotate among different hours during different four-hour periods for 40 days starting on Monday, Motta said, adding that additional details would be published on Friday.

The crucial oil sector is expected to be exempt from the cuts.

Motta said the measure would help raise the level of the reservoir and promised a “careful administration” of the dam.

Opposition critics say the situation is also the result of the government’s failure to boost thermoelectric generation as an alternative source of power, which would reduce the usage of the water in the reservoir.

Late socialist leader Hugo Chavez was forced to ration power during a drought in 2010, which proved to be one of his most difficult years in terms of his public approval rating.

The collapse of oil markets nearly two years ago has left Venezuela struggling to maintain its system of currency and price controls, leaving Venezuelans stuck in lines for hours to seek everything from corn flour to basic medicine.

Maduro says his government is the victim of an “economic war” led by political adversaries with the support of Washington.