Syria, Feb 10 : Hopes faded Thursday of finding more survivors after the earthquake that killed over 20,000 people in Turkey and Syria, as the first UN aid reached Syrian rebel-held zones.

Bitter cold has hampered the four-day 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.

"We found my aunt, but not my uncle," said Rania Zaboubi, a Syrian refugee who lost eight members of her family as other survivors sought loved ones' bodies.  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 as people slept early Monday in a region where many people 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 on Thursday, the first since the quake, an official at the Bab al-Hawa border crossing told AFP.