Iran on Sunday stepped up relief operations in shattered villages in its northeast after saying rescue operations were completed following a double earthquake which cost 227 lives and injured 1,380 people.

"Search and rescue operations have ended and we are now working to ensure survivors' needs in terms of shelter and food," Interior Minister Moustafa Mohammad-Najjar told state television as he announced the casualty toll.

He and other officials said the rubble left by Saturday's earthquakes hid no more survivors, making further rescue activities unnecessary.

Around half of the 600 villages located in the disaster zone, an area northeast of the city of Tabriz, were damaged, some of them badly, he said. A dozen or more were completely razed.

The first of the earthquakes registered a strong 6.4 on the moment magnitude scale, according to the US Geological Survey which monitors seismic activity worldwide.

The second, almost as strong at 6.3 on the scale, rumbled through just 11 minutes after the first. Many smaller aftershocks followed.

While Tabriz and nearby towns escaped with only relatively minor damage, many outlying villages where buildings are made of more flimsy mud and concrete bricks were decimated.

The interior minister said President Mahmoud Ahmadinejad had given orders for home reconstruction to begin immediately because of the harsh winter that the mountainous region experiences.

The region declared two days of mourning for the lives lost in the disaster.

An estimated 16,000 people remained homeless by the quakes or too afraid to return to cracked homes they feared unstable.

Iran's Red Crescent distributed thousands of tents and supplies of food and water to help them through the days ahead, and put up 4,000 emergency shelters in a sporting stadium.

It also said it turned down offers of help from Turkey, Taiwan, Singapore and Germany because Iran was able to cope with the disaster by itself.

The White House also stepped in to offer help and condolences to the people of Iran, with which Washington has no diplomatic relations and has been locked in a tense standoff for decades.

"The American people send the Iranian people our deepest condolences for the loss of life in the tragic earthquake in northeastern Iran," White House spokesman Jay Carney said in a statement.

"We stand ready to offer assistance in this difficult time," said the statement, which was addressed to the "Iranian people" and made no mention of the government of the Islamic republic.

Iran's ally, Syrian President Bashar al-Assad, sent his condolences to Ahmadinejad over the earthquakes, Syria's state news agency SANA reported, while Pope Benedict XVI and German Foreign Minister Guido Westerwelle voiced sympathies.

There were many stories of tragedy in Iran's disaster.

Zeinab, a 13-year-old girl seen outside a Red Crescent tent in the village of Mirza Ali Kandi, told AFP how she saw her eight-year-old brother and 16-year-old sister die before her eyes.

"I was outside my home playing when it (the first quake) happened. I ran inside looking for my brother and found him under a big pile of rubble. I tried to get him out. And then I heard my sister cry out and I turned and she has a big stone in her head, and I ran out," she said, sobbing.

"I wish it had been me, too, I wish I hadn't run out," she yelled, prompting her uncle to try to console her.

Others were more fortunate.

"I was working on my farm, on my tractor, and I felt the earth shake and I was thrown off the vehicle," a 40-year-old farmer in one hamlet, Qanbar Mehdizade, told AFP. His family, who had been working with him, survived.

AFP journalists in the zone saw many exhausted residents mourning their loved ones. Grieving women wailed over the bodies of the dead, many of whom were women and children.

"This village is a mass grave," said Alireza Haidaree, an emergency worker who supervised a bulldozer working in the village of Baje Baj, where 33 of the 414 inhabitants died.

"There are so many other villages that have been completely destroyed," he added.

Emergency workers from 14 provinces around Iran arrived to help on Saturday night, drawing on services and resources built up through the country's long experience in dealing with seismic instability.

Iran sits astride several major fault lines and is prone to frequent earthquakes, some of which have been devastating.

The deadliest in recent years was a 6.6-magnitude quake which struck the southeastern city of Bam in December 2003, killing 31,000 people -- about a quarter of the population -- and destroying the city's ancient mud-built citadel.