According to Turkey's disaster authority on Sunday, the devastating quake in the Turkish-Syrian border region has so far been followed by more than 6,000 aftershocks.

AFAD registered tremors "every three or four minutes" since the quake, around 40 of which were above magnitude 5, AFAD's Orhan Tatar told reporters in Ankara.

Tremors are expected to continue, taking a toll on already "traumatized locals," Tatar said.

Around 13,000 rescue workers were carrying out final efforts to save people from underneath the rubble in the worst-hit Turkish provinces of Hatay and Kahramanmaraş.

AFAD said the search-and-rescue mission is planned to be finalized later on Sunday.

Rescue teams recovered three people, including a child, alive from the debris of a collapsed apartment building. They had spent 296 hours since the quake under the rubble, state broadcaster TRT reported on Saturday. The 12-year-old child died of injuries at the hospital, according to state news agency Anadolu.

As Turkish Forestry Minister Vahit Kirisci told state broadcaster TRT, the affected area covers 103,000 square kilometres in Turkey alone, with 13.5 million people, or some 17% of Turkey's whole population.

Meanwhile, more than 1,100 kilometres to the west of the quake's epicentre, in Turkey's largest city Istanbul, authorities addressed the issue of earthquake preparedness in the future, to prevent a tragedy of this scale from happening again.

A total of 93 school buildings are set to be evacuated due to construction risks and will be rebuilt or strengthened, said the office of Istanbul's governor on Saturday. 

Turkey sits on the notorious Northern Anatolian fault line. A major quake in 1999 that struck Marmara region, including Istanbul, killed more than 18,000 people.

The country's authorities have been blasted for lax enforcement of construction regulations, which may have contributed to the high death toll. A total of 120 people, including contractors, have so far been arrested over responsibility in collapsed buildings, Anadolu reported.