Rescue workers recover more bodies three days after two powerful earthquakes struck northwest Iran, leaving more than 300 dead, but officials played down reports the number of casualties could still sharply increase.

Two powerful earthquakes, with magnitudes of 6.4 and 6.3, struck East Azerbaijan province in Iran on Saturday afternoon, flattening villages and injuring thousands of people around the towns of Ahar, Varzaghan, and Harees, near the provincial capital Tabriz.

A search team using sniffer dogs pulled out the body of a young woman in the village of Sorkhgav and were close to finding others, Fars new agency reported.

Another report, by Iran's Labour news agency, spoke of hundreds of villages having suffered severe damage, raising fears the number of dead could mount sharply as rescuers arrive in previously inaccessible areas.

But officials dismissed the estimates of a significant rise in fatalities, saying the eventual figure may be lower than already given.

"Many figures are based on speculation and have not been documented," provincial coroner Behram Samadi Rad said. "We cannot give a precise figure of the number of dead but we believe it will be under 300."

In Tehran, Karaj and Qom, thousands visited centres late into the night to donate blood, Press TV reported, including Iran's Olympic gold medal-winning weightlifter, Behdad Salimi.

"I truly feel terrible for the people of East Azerbaijan. I want to do what I can to help them. The most important thing is to donate blood because of the shortage," he said.

State television has showed extensive footage of air drops and officials handing out food rations and tents, following severe criticism the media ignored the national disaster and continued to broadcast normal schedules.

After visiting the afflicted area on Monday, Vice-President Mohammad Reza Rahimi announced emergency funds for the relief effort and appeared to indicate the government had not reacted quickly enough.

"In these conditions, any criticism the people have of us is acceptable and we must all work as hard as possible for their sake," Mehr news reported him as saying.

Iran's government faced criticism over its response to two earthquakes. President Mahmoud Ahmadinejad's trip to Saudi Arabia exposed him to barbs that he was not showing empathy with the disaster victims.

Meanwhile, more than 20 minor aftershocks added to torment of many who had lost their homes - some their loved ones - and were living in makeshift camps.