Twitter has been blocked on a number of networks across Turkey in the wake of the deadly earthquakes that have killed more than 9,500 people.
Twin earthquakes — the first a magnitude 7.8 and the second a 7.5 — hit Turkey and neighbouring Syria, on Monday. Tens of thousands of people are injured and missing and the there are still daily tremors causing thousands of families' homes to crumble.
Internet-monitoring group NetBlocks said on Wednesday that Twitter had been blocked on several networks across Turkey, with the filtering having been applied on major internet providers.
The incident comes as authorities raise concerns over disinformation online, although no formal explanation has been provided.
Alp Toker, the director of NetBlocks, said the coordinated nature of the restriction indicated that it was likely the result of a government order.
Mr Toker said network data showed the block was being carried out with software installed by telecommunications providers that can prevent specific websites and services from loading.
Network data indicated that the block was being done with software installed by telecommunications providers which could prevent specific websites from loading, he said in a statement to The Washington Post.
Toker highlighted the potential impact of the measure at a time when Twitter has been used as a key communication and coordination tool for aid-delivery efforts and rescues.
“Twitter has been an absolute lifeline in the aftermath of the earthquakes, both for rescuers to seek assistance and coordinate the provision of rescue equipment, and by those seeking missing loved ones,” he said.
“There is no obvious replacement to fill the gap.”
Turkey has a history of internet censorship and has been accused of restricting social media platforms during national emergencies before.
The social media platform has been blocked following terrorist attacks or political incidents, with officials arguing that it is safeguarding national security and preventing the spread of disinformation.
Turkish police have detained more than a dozen people since Monday's earthquake over social media posts criticising how President Recep Tayyip Erdogan's government has been dealing with the disaster, the Economic Times reports.
Rescuers are clawing through rubble with their bare hands despite the sub-zero temperatures and snow storms the region is also battling.
People have been plunged into homelessness and everyone is scrambling to rescue people trapped under toppled buildings.
In response, charities have set up emergency funds and rescue teams have descended on the region.
To make matters worse, the region where the earthquakes struck is home to significant numbers of Syrian refugees and internally displaced people.
They have already had to flee their homes from nearly 12 years of brutal war.
President Erdogan of Turkey said that 13 million people had been affected in the country and he declared a three-month state of emergency in 10 provinces.