President Tayyip Erdogan on Wednesday admitted there were problems with his government's initial response to a devastating earthquake in southern Turkey, amid anger from those left destitute and frustrated over the slow arrival of rescue teams.

Erdogan, who contests an election in May, said on a visit to the disaster zone that operations were now working normally and promised no one would be left homeless, as the combined reported death toll across Turkey and neighbouring Syria rose past 12,000.

Across a swathe of southern Turkey, people sought temporary shelter and food in freezing winter weather, and waited in anguish by piles of rubble where family and friends might still lie buried.

Rescuers were still finding some people alive. But many Turks have complained of a lack of equipment, expertise and support to rescue those trapped - sometimes even as they could hear cries for help.

"Where is the state? Where have they been for two days? We are begging them. Let us do it, we can get them out," Sabiha Alinak said near a snow-covered collapsed building in the city of Malatya where her young relatives were trapped.

There were similar scenes and complaints in neighbouring Syria, whose north was hard hit by Monday's huge quake.

Syria's ambassador to the United Nations admitted the government had a "lack of capabilities and lack of equipment," blaming more than a decade of civil war in his country and Western sanctions.

DEATH TOLL SURE TO RISE

The death toll from both countries was expected to rise as hundreds of collapsed buildings in many cities have become tombs for people who had been asleep when the quake hit.

In the Turkish city of Antakya, dozens of bodies, some covered in blankets and sheets and others in body bags, were lined up on the ground outside a hospital.

Melek, 64, bemoaned the lack of rescue teams. "We survived the earthquake, but we will die here due to hunger or cold."

Many in the disaster zone had slept in their cars or in the streets under blankets in freezing cold, fearful of going back into buildings shaken by the 7.8 magnitude tremor - Turkey's deadliest since 1999 - and by a second powerful quake hours later.

The confirmed death toll rose to 9,057 in Turkey on Wednesday, and in Syria had climbed to at least 2,950, according to the government and a rescue service operating in the rebel-held northwest.

Turkish authorities released video of rescued survivors, including a young girl in pyjamas, and an older man covered in dust, an unlit cigarette between his fingers as he was pulled from the debris.

Turkish officials say some 13.5 million people were affected in an area spanning roughly 450 km (280 miles) from Adana in the west to Diyarbakir in the east. In Syria, people were killed as far south as Hama, 250 km from the epicentre.

Some who died in Turkey were refugees from Syria's war. Their body bags arrived at the border in taxis, vans and piled atop flatbed trucks to be taken to final resting places in their homeland.

More than 298,000 people have been made homeless and 180 shelters for the displaced had been opened, Syrian state media reported, apparently referring to areas under government control, and not held by opposition factions.

In Syria, relief efforts are complicated by a conflict that has partitioned the nation and wrecked its infrastructure.

The delivery of U.N. humanitarian aid via Turkey to millions of people in northwest Syria could resume on Thursday after the long-running operation was halted by the quake, U.N. officials said.

In the Syrian city of Aleppo, staff at the Al-Razi hospital attended to an injured man who said more than a dozen relatives including his mother and father were killed when the building they were in collapsed.

ELECTION IMPACT

Erdogan, who declared a state of emergency in 10 provinces and sent troops to help, arrived in Kahramanmaras to view the damage and see the rescue and relief effort.

Speaking to reporters, a wail of ambulance sirens in the background, he said there had been problems with roads and airports but "we are better today".

"We will be better tomorrow and later. We still have some issues with fuel ... but we will overcome those too," Erdogan said.

He later condemned criticism of the government's response. "This is a time for unity, solidarity. In a period like this, I cannot stomach people conducting negative campaigns for political interest," Erdogan told reporters in the southern province of Hatay.

Nevertheless, the disaster will pose a challenge to Erdogan in the May election that was already set to be the toughest fight of his two decades in power. Istanbul's stock exchange operator suspended trading for five days in an unprecedented step.

Any perception that the government is failing to address the disaster properly could hurt his prospects. Conversely, analysts say he could rally national support around the crisis response and strengthen his position.

Syrian President Bashar al-Assad appears to be seeking political advantage from the quake, pressing for foreign aid to be delivered through his territory as he aims to chip away at his international isolation, analysts said.

Twitter was restricted in Turkey on Wednesday, the Netblocks internet observatory said.

The move "comes as the public come to rely on the service in the aftermath of a series of deadly earthquakes," said Netblocks, which tracks connectivity across the globe.

Cyber rights expert and professor at Istanbul Bilgi University Yaman Akdeniz said it was not clear what caused the restriction, adding that access to Tiktok was also limited in Turkey.

"How come Twitter is restricted on a day communication saves lives?," the head of the DEVA opposition party, Ali Babacan, said on Twitter.

The Transportation and Infrastructure Ministry, which could impose such restrictions, was not available for comment.