Syria has suffered a massive power blackout across the country due to “unknown reasons”, state media said.
Officials were cited as saying power had been cut in all provinces and teams were trying to determine the cause.
The electricity ministry said power was being restored and service would resume by midnight (22:00 GMT), TV reported.
In most parts of war-torn Syria, electricity is already available only two to four hours a day, if at all. However, nationwide blackouts are rare.
Meanwhile, the UN’s special envoy said a partial truce that began on Saturday was holding but remained fragile.
Staffan de Mistura told reporters in Geneva that violence had been “greatly reduced”, despite incidents in the provinces of Homs, Hama, Latakia and Damascus. “Success is not guaranteed but progress is visible,” he added.
Both the opposition and the government have accused each other of violating the cessation of hostilities agreement brokered by the US and Russia, which does not include the jihadist groups Islamic State (IS) and al-Nusra Front.
Mr de Mistura also said that while he planned to reconvene talks aimed at ending the five-year conflict in Syria next Wednesday, their format was flexible and some parties might turn up days later.
UN humanitarian adviser Jan Egeland said progress had been made in getting aid to besieged areas of Syria, and that there would be further attempts at air-drops of aid over the eastern city of Deir al-Zour, where 200,000 people are surrounded by IS militants, within days or weeks.
Internet services ‘halted’
The official Sana news agency cited a source at the ministry of electricity as confirming that “there is a power cut in all provinces of Syria”.
“Engineers and technicians are working on finding out why this sudden power cut happened in order to fix it promptly and restore electricity in the next few hours,” the source added.
The Syrian Observatory for Human Rights, a UK-based group that monitors the Syrian conflict through a network of sources, also reported power cuts in the “vast majority” of provinces, while Damascus residents told the AFP news agency that there had been a cut in the capital since 13:00 (11:00 GMT).
Sana also quoted the state-owned Syrian Telecommunication Establishment as saying internet services were partially halted “as a result of sudden damage to one of the network hubs and repair teams have been sent to fix it”.
The government has blamed previous blackouts on rebel attacks, while the UN has also noted that access to electricity has been restricted as a weapon of war.
Earlier on Thursday, Amnesty International said Russian and Syrian government forces appeared to have been deliberately and systematically targeting health facilities in the northern province of Aleppo in the past 12 weeks.
The human rights group reported that it had gathered “compelling evidence” of at least six deliberate attacks on hospitals, medical centres and clinics.
They killed three civilians, including one medical worker, and injured 44 others.
Amnesty said the attacks, which it said were flagrant violations of international humanitarian law, appeared to be aimed at paving the way for government ground forces to advance in the weeks before the cessation of hostilities took effect.
“Hospitals, water and electricity are always the first to be attacked. Once that happens, people no longer have services to survive,” one doctor in the town of Anadan was quoted as saying.