The Death toll in massive earthquake in Turkey and Syria has climbed on 21000.
Now the bitter cold hampered the search of thousands of flattened buildings and threatened the lives of many quake victims who are without shelter and drinking water.
Relatives were left scouring body bags laid out in a hospital car park in Turkey's southern city of Antakya to search for missing relatives, an indication of the scale of the tragedy.
Chances of finding survivors have dimmed now that the 72-hour mark that experts consider the most likely period to save lives has passed.
The 7.8-magnitude quake struck early Monday as people slept, in a region where many had already suffered loss and displacement due to Syria's civil war.
But in a potentially life-saving development, an aid convoy reached rebel-held northwestern Syria earlier in the day, the first since the quake.
A decade of civil war and Syrian-Russian aerial bombardment had already destroyed hospitals, collapsed the economy and prompted electricity, fuel and water shortages.
UN Secretary-General Antonio Guterres urged the Security Council to authorise the opening of new cross-border humanitarian aid points between Turkey and Syria to deliver aid.
Four million people living in rebel-held areas of northwest Syria have had to rely on the Bab al-Hawa crossing as part of a cross-border aid operation authorised by the Security Council nearly a decade ago.
"This is the moment of unity, it's not a moment to politicise or to divide but it is obvious that we need massive support," Guterres said.
Temperatures in the Turkish city of Gaziantep plunged to minus five degrees Celsius (23 degrees Fahrenheit) early Thursday, but thousands of families spent the night in cars and makeshift tents -- too scared or banned from returning to their homes.
Parents walked the streets of the city -- close to the epicentre of Monday's earthquake -- carrying their children in blankets because it was warmer than sitting in a tent.
Gyms, mosques, schools and some stores have opened at night. But beds are still at a premium and thousands spend the nights in cars with engines running to provide heat.
"I fear for anyone who is trapped under the rubble in this," said Melek Halici, who wrapped her two-year-old daughter in a blanket as they watched rescuers working into the night.
International rescuers have said the intense cold has forced them to weigh whether to use their limited fuel supplies to keep warm or to carry out their work.
Donors are on conference
Dozens of nations, including China and the United States have pledged to help.
The World Bank said it would give $1.78 billion in aid to Turkey to help relief and recovery efforts.
Immediate assistance of $780 million will be offered from two existing projects in Turkey, said the bank, while an added $1 billion in operations is being prepared to support people affected amid recovery and reconstruction.
In addition to a staggering human toll, the quake's economic cost appears likely to exceed $2 billion and could reach $4 billion or more, Fitch Ratings said.