Venezuelan opposition leader Juan Guaidó has acknowledged that there can only be a change of government with the support of the armed forces.
Military chiefs have so far remained loyal to President Nicolás Maduro.
Mr Guaidó declared himself interim leader in January and says he is supported by “almost 90%” of Venezuelans. He also has US backing.
On Sunday Venezuelan authorities said they would shorten the working day and keep schools closed due to power cuts.
Offices would stop working at 14:00 local time “to achieve consistency in the provision of electricity”, Communications Minister Jorge Rodriguez said on state TV.
Mr Guaidó told the BBC that the frequent power cuts and water shortages – which have hit hospitals, public transport, water and other services – were driving intense public anger against Mr Maduro’s government.
“We have a situation now with protests in more than 20 districts of the capital, Caracas, and in all Venezuelan states. People are demanding that power and water supplies be restored, but also for the usurper, Nicolás Maduro, to go, which is the main message,” he said.
The government has claimed the blackouts are the result of sabotage in an effort to force Mr Maduro from office.
However Mr Guaidó said Mr Maduro could not be removed unless Venezuela’s military abandons him.
“The support and the backing of the armed forces will be necessary in order to achieve democratic and peaceful change in Venezuela in all areas, including to protect protesters from the pro-government armed militias,” he said.
Mr Guaidó – who the government says will be barred from holding further public office for 15 years – dismissed the recent reported arrival of Russian troops in Venezuela as a “provocation” by Mr Maduro to “try to show some sort of support that he really doesn’t have”.
“The Russians haven’t made any concrete moves, they haven’t shown any real support apart from, perhaps, some diplomatic statements,” he said.
On Saturday the Red Cross (IFRC) said it could begin distributing crucial aid supplies to crisis-hit Venezuela in two weeks. IFRC head Francesco Rocca said the group could initially help 650,000 suffering a lack of food and medicine.
In February, the government blocked the delivery of US-backed aid convoys, which it said were a veiled US invasion.
What’s the background?
Mr Maduro narrowly won a presidential election in April 2013 after the death of his mentor, President Hugo Chávez. He was elected to a second term in May 2018 in an election seen as flawed by international observers.
Venezuela has experienced economic collapse – inflation was 800,000% last year. Three million people have left.
Mr Guaidó has accused President Maduro of being unfit for office, and won the support of many in the country as well as US and EU leaders.
The Maduro government is becoming increasingly isolated but Moscow has expanded co-operation with Caracas – increasing arms sales and extending credit.