HARARE, Zimbabwe – Nationwide power outages shut down basic services across Zambia and Zimbabwe as anger mounted in South Africa over power cuts that have wreaked havoc in the continent’s economic hub.

There was no immediate explanation for Saturday night’s blackout, which hit Zambia and neighboring Zimbabwe almost simultaneously. It was unclear whether there was a connection.

Power was restored in Zambia about eight hours later, but Zimbabweans remained without electricity, water, telephones and traffic signals for much of Sunday.

Power and water outages occur daily in Zimbabwe’s crumbling economy but not on a national scale. Zimbabwe state radio, running on generators, reported the outage was caused by a major breakdown but did not elaborate. The state power utility gave no explanation as power returned in some areas Sunday afternoon.

In one apartment district in central Harare, cheers erupted when the electricity came on, replaced by jeers and catcalls when it went off again minutes later.

Zimbabwe imports about 40 percent of its power from regional neighbors and is in arrears in hard currency for most of the imports. It is suffering chronic shortages of hard currency, local money, food, gasoline and most basic goods.

One of its main suppliers, South Africa, is having problems with large parts of the country suffering blackouts that often last several hours.

State utility company Eskom said Sunday it had stopped supplying electricity to Zimbabwe, Botswana and Namibia because of the dire shortage at home. Normally about 95 percent is used locally and the rest is sold abroad.

“When we don’t have enough capacity for domestic use we don’t sell electricity. There is no surplus so there are no exports,” Eskom spokesman told the South African Press Association.

Outraged commuters set fire to six trains near Pretoria on Friday evening after being delayed for two hours because of power outages.