Recession-wracked Venezuela is to ration electricity in 10 of its most populous and industrialized states, including metropolitan Caracas, the socialist government said.
It is the latest drastic measure to alleviate a severe electricity crisis which President Nicolas Maduro and his government blame on the El Nino weather phenomenon that causes drought.
Critics say it's the result of years of economic mismanagement.
Luis Motta Dominguez, minister for electric power, made the announcement during a televised broadcast and said further details would be released in the coming days.
Maduro is under growing pressure from the center-right opposition, which vowed to oust him when it took control of the legislature in January after winning elections, blaming him for the crippling economic crisis.
Venezuela's economy has plunged along with the price of the oil on which it relies for foreign revenues. Shortages of medicines and goods such as toilet paper and cooking oil are widespread.
Maduro blames the collapse on an "economic war" by capitalists.
Last week, his government said it was shifting its time zone forward by 30 minutes to save power.
Other measures include giving government workers an extra day off each week for the next two months, and Maduro has urged Venezuelan women to stop using their hairdryers.
"The greatest power consumption is residential," Motta said, speaking at the Guri hydroelectric plant.
The water level in the dam feeding the facility in Venezuela's southeast, which supplies 70 percent of the country's grid, "continues to decline steadily and is approaching the minimum operating height," he added, saying it left authorities no option but to ration.
Maduro said Wednesday that residential energy-saving targets had not been met, necessitating the rationing that "will save the Guri" from collapse.
Water levels in the country's 18 hydroelectric dams have dropped to dangerously low levels, and citizens regularly suffer blackouts and water rationing.
Venezuela has the world's largest proven oil reserves, but the government has resisted using crude to generate electricity, calling it inefficient.
Maduro's other measures to cut electricity use include reducing the workday to six hours for ministries and state companies and ordering them to lower their electricity consumption by 20 percent.
He has also ordered shops and hotels to ration electricity, obliging them to generate their own power for several hours a day.
Shopping centers have cut back their hours since that plan was introduced.
Analysts, however, warn that the measures being introduced will further damage the productivity of the country, which is in serious economic straits. Its inflation rate of 180 percent for 2015 is the highest in the world, and basic goods are scarce.
Some workers complain that although they might be getting more time off, they don't have any money to enjoy it. So they end up doing more household chores or lining up at the supermarket for rare subsidized food items.
Maduro reached the halfway point of his mandate this week, leaving him prey to legal measures to drive him from office.
He has vowed to hold on to power and press on with the socialist "revolution" launched by his late predecessor Hugo Chavez.