ANKARA, Turkey (AFP) - The causes of Turkey's biggest power cut in over 15 years that deprived most of the country of electricity remained shrouded in mystery on Wednesday, with the government under pressure to give answers ahead of June 7 legislative elections.
The cut - the worst since the earthquake of 1999 - halted metro services in Turkey's major cities, created huge traffic jams and inflicted losses on businesses.
The problem appears to have started at a power plant in the Aegean region of Turkey and then spread in a "domino effect" across the national grid in circumstances yet to be fully explained.
At one point, the only Turkish region not affected by the cut was Van province in the east which imports all of its electricity from neighbouring Iran.
The disorder was a major blow for the government and President Recep Tayyip Erdogan, who at the time was out of the country in Slovakia with key ministers including Energy Minister Taner Yildiz.
Critics of the government mocked its response, gleefully pointing out the emblem of the ruling Justice and Development Party (AKP) is a light bulb.
"The state collapsed. What went out in the entire country was the light bulb of the ruling party," commentator Ertugrul Ozkok wrote in the Hurriyet daily.
"The light bulb of the ruling party well and truly broke and this time for good," said Yusuf Halacoglu, MP for the opposition Nationalist Movement Party (MHP).
As well as the irritation caused to millions of Turks the length of the day-long power cut that affected both Istanbul and Ankara carried a heavy financial cost.
According to an estimate published by the Ankara Chamber of Commerce, the cost to the Turkish economy of single-day cut could amount to one billion lira (S$530 million).
The AKP is widely expected to win the June 7 elections but it needs every vote to secure the majority it wants to change the constitution and boost the powers of the president.
'NOT READY FOR DISASTERS'
The authorities have left all possibilities open as to the cause of the calamity from a technical fault, human error to even terrorism of a cyber-attack.
Prime Minister Ahmet Davutoglu said an investigation was in progress but no further details were given Tuesday. Conspiracy theories over the cause were rife on the Internet.
"This issue is being investigated. There is no clear result," he said, adding every possibility was being examined, including "terror".
The power cut coincided with the kidnapping of a prosecutor in Istanbul that ended with his death. But the authorities blasted the opposition for suggesting the events could be related.
Turkey's lack of its own energy resources has always been a strategic weak point and it imports most of its fossil fuels from Iran and Russia.
But with Erdogan seeking to vault Turkey into one of the world's top 10 economies by 2023, the country is now making a significant investment in nuclear power.
Russia is due to build Turkey's first nuclear power plant at Akkuyu while a second facility is planned in the Black Sea city of Sinop with the help of Japan.
A third plant is also scheduled and officials have spoken of nuclear energy providing 20 per cent of Turkey's energy needs by 2030.
But for now, the power cut has again highlighted Turkey's fallibility on energy as Erdogan seeks to make the country a major world power.
"The power cut showed that Turkey is not ready to confront disasters," said Hakan Celik, anchorman on CNN-Turk.