An elderly Georgian woman was scavenging for copper to sell as scrap when she accidentally sliced through an underground cable and cut off internet services to all of neighbouring Armenia, it emerged on Wednesday.

The woman, 75, had been digging for the metal not far from the capital Tbilisi when her spade damaged the fibre-optic cable on 28 March.

As Georgia provides 90% of Armenia's internet, the woman's unwitting sabotage had catastrophic consequences. Web users in the nation of 3.2 million people were left twiddling their thumbs for up to five hours as the country's main internet providers - ArmenTel, FiberNet Communication and GNC-Alfa – were prevented from supplying their normal service. Television pictures showed reporters at a news agency in the capital Yerevan staring glumly at blank screens.

Large parts of Georgia and some areas of Azerbaijan were also affected.

"It was a 75-year-old woman who was digging for copper in the ground so that she could sell it for scrap," said a spokesman for Georgia's interior ministry said yesterday.

Dubbed "the spade-hacker" by local media, the woman – who has not been named – is being investigated on suspicion of damaging property. She faces up to three years in prison if charged and convicted.

A spokesman for Georgia's interior ministry said the woman was temporarily released "on account of her old age" but could face more questioning.

The damage was detected by a system monitoring the fibre-optic link from western Europe and a security team was immediately dispatched to the spot, where the woman was arrested. The interior ministry said she had no accomplices.

The cable is owned by the Georgian railway network. It is heavily protected, but landslides or heavy rain may have exposed it to scavengers.

Pulling up unused copper cables for scrap is a common means of making money in the former Soviet Union. Some entrepreneurs have even used tractors to wrench out hundreds of metres of cable from the former nuclear testing ground at Semipalatinsk in Kazakhstan.