GAZIANTEP, Turkey — With hope of finding survivors fading, stretched rescue teams in Turkey and Syria searched Wednesday for signs of life in the rubble of thousands of buildings toppled by the world’s deadliest earthquake in more than a decade. The confirmed death toll approached 12,000.

Turkish President Recep Tayyip Erdogan visited the especially hard-hit Hatay province, where more than 3,300 people died and entire neighborhoods were destroyed. Residents there have criticized the government's response, saying rescuers were slow to arrive.

Erdogan, who faces a tough battle for reelection in May, acknowledged “shortcomings” in the response to Monday's 7.8 magnitude quake but said the winter weather had been a factor. The earthquake destroyed the runway in Hatay's airport, further disrupting the response.

“It is not possible to be prepared for such a disaster," Erdogan said. “We will not leave any of our citizens uncared for.” He also hit back at critics, saying ”dishonorable people" were spreading “lies and slander” about the government's response.

Turkish authorities say they are targeting disinformation, and an internet monitoring group said access to Twitter was restricted despite it being used by survivors to alert rescuers.

Search teams from more than two dozen countries have joined tens of thousands of local emergency personnel in Syria and Turkey. But the scale of destruction from the quake and its powerful aftershocks was so immense and spread over such a wide area — including a region isolated by Syria’s ongoing civil war — that many people were still awaiting help.

Experts said the survival window for those trapped under the rubble or otherwise unable to obtain basic necessities was closing rapidly. At the same time, they said it was too soon to abandon hope.

“The first 72 hours are considered to be critical,” said Steven Godby, a natural hazards expert at Nottingham Trent University in England. “The survival ratio on average within 24 hours is 74%, after 72 hours it is 22% and by the fifth day it is 6%.”

Rescuers at times used excavators or picked gingerly through debris. With thousands of buildings toppled, it was not clear how many people might still be caught in the rubble.

In the Turkish city of Malatya, bodies were placed side by side on the ground and covered in blankets while rescuers waited for vehicles to pick them up, according to former journalist Ozel Pikal, who said he saw eight bodies pulled from the ruins of a building.

Pikal, who took part in the rescue efforts, said he thinks at least some of the victims froze to death as temperatures dipped to minus 6 degrees Celsius (21 Fahrenheit).

“As of today, there is no hope left in Malatya,” Pikal said by telephone. “No one is coming out alive from the rubble.”

Road closures and damage in the region made it hard to access all the areas that need help, he said, and there was a shortage of rescuers where he was.

“Our hands cannot pick up anything because of the cold,” said Pikal. “Work machines are needed.”

The region was already beset by more than a decade of civil war in Syria. Millions have been displaced within Syria itself and millions more have sought refuge in Turkey.

Turkey's president said the country’s death toll passed 9,000. The Syrian Health Ministry said the death toll in government-held areas climbed past 1,200. At least 1,600 people have died in the rebel-held northwest, according to the volunteer first responders known as the White Helmets.

That brought the overall total to nearly 12,000. Tens of thousands more are injured.

Stories of rescues continued to provide hope that some people still trapped might be found alive. A crying newborn still connected by the umbilical cord to her deceased mother was rescued Monday in Syria. In Turkey's Kahramanmaras, rescuers pulled a 3-year-old boy from the rubble, and rescuers sent by the Israeli military saved a 2-year-old boy.

But David Alexander, a professor of emergency planning and management at University College London, said data from past earthquakes suggested the likelihood of survival was now slim, particularly for individuals who suffered serious injuries.

“Statistically, today is the day when we’re going to stop finding people,” he said. “That doesn’t mean we should stop searching.”

Alexander cautioned that the final death toll may not be known for weeks because of the sheer amount of rubble.

The last time an earthquake killed so many people was 2015, when 8,800 died in a magnitude 7.8 quake in Nepal. A 2011 earthquake in Japan triggered a tsunami, killing nearly 20,000 people.

Many of those who survived the earthquake lost their homes and were forced to sleep in cars, government shelters or outdoors amid rain and snowfall in some areas.

“We don’t have a tent, we don’t have a heating stove, we don’t have anything. Our children are in bad shape,” Aysan Kurt, 27, said. “We did not die from hunger or the earthquake, but we will die freezing from the cold.”

The disaster comes at a sensitive time for Erdogan, who faces an economic downturn and high inflation. Perceptions that his government mismanaged the crisis could hurt his standing. He said the government would distribute 10,000 Turkish lira ($532) to affected families.

Kemal Kilicdaroglu, the leader of Turkey’s main opposition party, blamed the devastation on Erdogan’s two-decade rule, saying he had not prepared the country for a disaster and accusing him of misspending funds.

In their effort to crack down on disinformation related to the earthquake response, police said they had detained 18 people and identified more than 200 social media accounts suspected of “spreading fear and panic.”

Global internet monitor NetBlocks said access to Twitter was restricted on multiple internet providers in Turkey. Trapped survivors have used Twitter to alert rescuers and loved ones, while others have taken to the social network to criticize the government's response.

There was no official comment on the restrictions. The government has periodically restricted access to social media during national emergencies and terror attacks, citing national security.

In Syria, aid efforts have been hampered by the ongoing war and the isolation of the rebel-held region along the border, which is surrounded by Russia-backed government forces. Syria itself is an international pariah under Western sanctions linked to the war.

The European Union said Wednesday that Syria had asked for humanitarian assistance to help earthquake victims. An EU representative insisted the bloc's sanctions against the Syrian government had no impact on its potential to help.

The U.N. humanitarian coordinator for Syria, Muhannad Hadi, said Wednesday that there was still no access to the Bab al-Hawa border crossing into rebel-held Syria — the only terminal where U.N. aid can be delivered — because of damaged roads.

Using other crossings, or sending the aid across conflict lines from Damascus, requires “multiple levels of coordination between different parties, security, humanitarian, NGOs,” he said. “It’s not a straightforward operation.”

Critics have accused the Syrian government of deliberately slowing down the process to cut off support to rebel-held areas.

Turkey sits on top of major fault lines and is frequently shaken by earthquakes. Some 18,000 were killed in similarly powerful earthquakes that hit northwest Turkey in 1999.