The White Helmets, Syria's Civil Defence in opposition-held areas, announced an official mourning period on Monday to pay tribute to victims of the earthquake in Syria and Turkey.
The humanitarian response group say they will raise their flags at half mast across all of their centres in Syria for a week, as they declared February 6 an annual national day of mourning.
On February 6, a 7.8-magnitude earthquake struck the region before dawn on Monday and was followed by a series of aftershocks, including a 7.5-magnitude quake.
The tragedy has left at least 37,000 people dead, and search operations for survivors still under the rubble will soon come to a close, the rescue group announced on Tuesday.
"The White Helmets declare official mourning throughout Syria, and we will fly the flags at half-mast for 7 days… to mourn the souls of the earthquake victims in #Syria and #Turkey… we declare February 6 as a national day of mourning every year," they said in a statement.
"The indications we have are that there are not any [more survivors] but we are trying to do our final checks on all sites," said Raed al Saleh who heads the White Helmets group that has carried out most rescue operations in the devastated regions outside Syrian government control in the north.
The group’s rescue operations have deeply touched hearts across the globe. One of their rescue missions, in which an entire family was rescued from under the rubble of their house to the sound of dozens of cheers, went viral across social media.
However, many of the children they rescued lost their parents and families in the quake.
The volunteers have been working tirelessly through cold nights to save survivors of the tragedy, the intensity of which has also given them deep pain.
Medics say at least 3,688. People have died across Syria, as 31,643 have died in Turkey. The toll has barely changed in Syria for several days and is expected to rise.
The war-torn country is of particular concern, as it has already been racked by 12 years of civil war.
The United Nations held an emergency meeting on Monday on how to boost aid to rebel-held areas – where many citizens fled after fleeing the regime’s crackdown on pro-democracy protests - as anger grows over a sluggish international response to Syrians affected.