Opposition leaders and social media users criticised the throttling of the platform, which has helped people share information on arriving aid and the location of those still trapped in rubble after the initial tremor on Monday.

President Tayyip Erdogan's government has blocked social media in the past and focused in recent months on fighting what it calls "disinformation", which it said prompted the block on Wednesday.

It restored full access to Twitter early on Thursday as the quake's death toll in Turkey and neighbouring Syria shot past 17,000.

President Tayyip Erdogan's government "lost its mind and... the result is cries for help being heard less. We know everything you're trying to hide," main opposition CHP leader Kemal Kilicdaroglu said after the block was imposed on Wednesday afternoon.

A government official who requested anonymity said the move had temporarily interrupted real calls for help, but that action was taken quickly and the service returned to normal.

"This had to be done because in some accounts there were untrue claims, slander, insults and posts with fraudulent purposes," the official told Reuters, citing efforts to steal money under the pretense of collecting aid.

Turkish officials held talks with Twitter on Wednesday and said they expected cooperation in fighting disinformation during relief work, Deputy Transport Minister Omer Fatih Sayan said.

Erdogan's communications director, Fahrettin Altun, said Twitter cooperated in the meeting and pledged to support Turkey's efforts, and officials look forward to working with it "over the next few days and weeks".

"Disinformation is humanity's common enemy and a grave threat to democracy, social peace, and national security," he said on Twitter on Thursday.

Last October, Turkey's parliament adopted a law under which journalists and social media users could be jailed for up to three years for spreading "disinformation", raising concerns among rights groups and European countries about free speech.

Erdogan's ruling party had said a law was needed to tackle false accusations on social media, and it would not silence opposition. The issue is of growing significance with elections scheduled to be held by the middle of this year.

A Reuters investigation last summer showed how the mainstream media has become a tight chain of command of government-approved headlines, while the smaller independent and opposition media face the brunt of regulatory penalties.

The Twitter block also drew an angry response from opposition DEVA party leader Ali Babacan, a former economy minister and Erdogan ally.

"How can Twitter be blocked on a day when communication is saving lives? What sort of ignorance this," Babacan said late on Wednesday.

The pro-Kurdish HDP party said Twitter had played a crucial role in organizing aid for those affected by the quakes and that blocking social media would only cause more death.