China has issued an urgent appeal for earth-moving equipment to help rescue efforts in the country's south-west following Monday's earthquake.

On Thursday the confirmed death toll rose above 19,500, and late in the day state television said it was likely that more than 50,000 people had died, as hopes of finding more survivors in the rubble of destroyed towns and cities began to fade.

"If there are some survivors under such conditions, it would be a matter of luck, or a miracle," said Zhang Zhoushu, vice director of the state-run China Earthquake Disaster Prevention Centre.

The government has issued a rare international call for emergency equipment, saying it needs cranes, shovels and hammers.

Help accepted from Japan and Taiwan
After previously turning down international offers of help, including an offer of assistance from Australia, China said it would allow a contingent of 60 Japanese rescue specialists and sniffer dogs to join the relief effort in worst-hit Sichuan province.

Another aid team from Taiwan, including medical personnel, has also been accepted by Beijing.

Xinhua news agency says around 10 million people are severely affected by the aftermath of the earthquake, which is known to have killed nearly 15,000 people.

Massive search and rescue effort continuing
Beijing has deployed 110 helicopters into the quake zone, and authorities have sent thousands of troops and medical workers into the region.

Many communities have gone without water for nearly four days, and people are desperate for food and essential supplies.

CNN reporter John Vause, who is in Beichuan province, said desperate parents were continuing their vigil outside a collapsed school as rescue workers searched the rubble.

"Some of the bodies were embracing eachother, others were huddled under desks with their hands over the heads as if they were protecting themselves from the debris," he said.

"For the parents, it's agonising to say the least. Each time a body is brought out there is obviously heartbreak, and they're still clinging to hope that maybe, maybe there'll still be their children alive under the huge pile of rubble that was once a five-story tall building made of concrete and steel."

Mr Vause said he had just returned from Beichuan City, which he called "a scene of utter and total devastation".

"Entire buildings have collapsed, in fact almost every building in that city has either been destroyed or is badly damaged," he said.

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