"I express heartfelt thanks to the foreign governments and international friends," Mr Hu was quoted as saying by the state-run Xinhua news agency.
Offers of help in the relief effort from home and abroad have now surpassed $860m (£440m), Chinese officials say.
The first aid supplied by the US has arrived, with an air force plane loaded with tents, lanterns and 15,000 meals landing in Sichuan's provincial capital, Chengdu.
However, a British rescue team standing by in Hong Kong is returning home after being refused permission to travel to the earthquake zone.
Rescue efforts have resumed in Beichuan, after the city was evacuated amid fears that it could be engulfed by a river bursting its banks.
The city, which lies near the epicentre of the quake, was reduced to ruins.
Aftershocks
There are still stories of survivors being pulled from the rubble.
One man who was rescued on Sunday, Tang Xiong, had only had slight bruises and was conscious when he was rescued in Beichuan county 139 hours after the quake, Xinhua said.
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The rescue operation continues
A 53-year-old man was pulled from the rubble in the town of Yingxiu in Wenchuan county after surviving for 148 hours, state media said.
Rescue workers worked for eight hours to save him.
But other stories illustrated how hopes for those beneath the rubble are fading fast.
Video pictures emerged of a man wedged under fallen masonry. He was still alive, and was lent a phone to speak to his wife.
"I don't hold out much hope of surviving," he told her.
Rescuers later managed to extract him, but not in time to save his life.
Strong aftershocks have been continuing, some causing landslides.
One measuring 6.0 on Sunday killed three people and injured more than 1,000, Xinhua reported.
Three giant pandas are missing from the Wolong Nature Reserve, Xinhua reports. All the pandas at the reserve were initially reported safe.
Nuclear facilities in the affected area have been confirmed to be safe, the ministry of environmental protection's Nuclear Safety Department said, Xinhua has reported.
China has a research reactor, two nuclear fuel production sites and two nuclear weapon facilities in Sichuan, all between 60-145km (40-90 miles) from the epicentre, according to the French Institute for Radiological Protection and Nuclear Safety.
Persistent rain compounded the misery for millions of people made homeless by the quake. And the weather may deteriorate, with rains turning torrential later in the week, potentially triggering landslides, Chinese forecasters said.
And the World Health Organization warned that rising temperatures in Sichuan, combined with a lack of clean water and waste disposal, and cramped conditions in makeshift camps, could be conducive to outbreaks of disease.
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