Heavy rain and snow has hampered the emergency effort in southern Iran where an earthquake is estimated to have killed more than 500 people.
Many face the prospect of a night without shelter
Iranian Red Crescent workers have been moving people to nearby towns and cities in Kerman province.
They also worked with sniffer dogs and mountain rescue teams to bring shelter to those in more remote areas.
Whole villages were demolished when the 6.4-magnitude quake struck early on Tuesday morning.
The 11-second quake was centred near Zarand town, 740km (460 miles) from the capital, Tehran.
Some 30,000 people in about 40 villages spread over a wide, mountainous area have been affected.
There have been harrowing scenes of grief. Parents who lost children and their homes sat in the rain and cried. Others were seen clawing at the rubble to find survivors and retrieve corpses.
Dr MJ Fadaee, deputy to the regional governor of Kerman province, told the BBC News website that the priority was to get help to those left without shelter.
But he said villages had been inaccessible by road during parts of the day, and helicopters had trouble reaching areas because of the bad weather.
"The most serious need for those people affected is for temporary camps and blankets and plastic materials," he said.
"We have severe rain and snow so we must put up tents and gather waterproof material to be sent to the regions affected."
People were asked to stay outdoors despite the heavy rain because of aftershocks, and they were told not to use mobile telephones except for emergencies to prevent a breakdown in the service.
Gas was shut off in the area as a precaution, and school classes were held outdoors.
As night fell, survivors huddled around fires to keep warm.
Dr Fadaee said 1,600 people were involved in the rescue effort, helping to move survivors to temporary accommodation.
Iranian relief officials have said they are benefiting from their experience of the devastating earthquake in the historic city of Bam, some 200km (120 miles) away, in December 2003, that killed around 30,000 people.
RECENT MAJOR EARTHQUAKES
26 December 2004: Hundreds of thousands killed in Asian tsunami following quake off Indonesia
26 December 2003: More than 26,000 die in Bam, southern Iran
26 January 2001: Nearly 20,000 killed, more than a million homeless in Gujarat, India
17 August 1999: Earthquake in Izmit and Istanbul, Turkey, kills more than 17,000
21 June 1990: Around 40,000 die in tremor in Gilan, Iran
Iran has said it does not need international aid this time.
The BBC's Frances Harrison in Tehran says the casualties could have been far worse had the earthquake struck a major city instead of a more sparsely populated area.
She says the focus of this earthquake was four times deeper underground than in Bam, lessening the impact.
Iran has at least a minor earthquake almost every day.
The United Nations says it is the worst-hit country in the world in terms of earthquakes.
Seismologists say this is because Iran is at the confluence of three of the Earth's plates, and is literally being squeezed by them.