Thousands of websites in Georgia, including those of the president, courts and media, have been hacked in a massive cyberattack.
The affected pages displayed a photo of Georgia's self-exiled former President Mikheil Saakashvili with an inscription "I'll be back!", Georgia's Interpress news agency reported on Monday.
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There has been no immediate claim of responsibility.
Proservice, the owner of one of the affected servers, said on Monday evening it had so far managed to recover about 50 percent of the 15,000 websites hosted on its servers.
"Today, October 28, one of the largest cyberattacks on the cyber space of Georgia took place at dawn," Interpress quoted Proservice as saying.
"One of the targets of the attack is a server owned by Proservice, which hosts websites of state agencies, the private sector and media organisations. As a result of the attack, about 15,000 web pages located on the servers of the company were broken."
Georgian President Salome Zurabishvili's website was "attacked by hackers this afternoon", her spokeswoman told AFP news agency.
"Law enforcement agencies are investigating the incident," Sopho Jajanashvili said.
Interpress said the website for Georgia's general jurisdiction courts, as well as the pages of a number of government agencies, NGOs and media outlets were also hit.
The cyberattack also affected servers of Georgia's two major broadcasters, Maestro and Imedi TV, temporarily sending the television stations off the air.
Georgia's interior ministry said it had launched an investigation.
Previous incidents
In 2008, in the run-up to and during the war between Russia and Georgia, Tbilisi accused Moscow of an all-out cyberattack against the websites of nearly all government agencies and the country's leading banks.
Russia denied the allegations but said that "individuals in Russia" might have been responsible.
Western cyber-analysts alleged that Russia's security services had likely played a key role in organising those attacks.
The United States Cyber Consequences Unit said the 2008 attacks highlighted the need for international cooperation on cybersecurity.
The two countries' brief but bloody conflict marked the culmination of the spiralling tensions over Georgia's bid to forge closer ties with the West, which has long angered Tbilisi's Soviet-era master, Russia.
Saakashvili lives in a self-imposed exile in Ukraine after his second term as president ended in 2013.
The fervently pro-Western reformist former leader is wanted in Tbilisi on charges of abuse of power, which he denies.
A number of former top officials from Saakashvili's administration were jailed after his party lost in the 2012 parliamentary elections to the current ruling party, Georgian Dream, headed by oligarch Bidzina Ivanishvili.
Opposition parties and Georgia's Western allies have denounced the prosecutions as a political witch-hunt.
