The shocks endangered survivors and rescuers alike, threatening to bring down or shift the mangled concrete and steel remains of buildings.

International search teams, using sniffer dogs and heat-seeking equipment, are clawing through dozens of toppled buildings in the hope of finding more people alive.

Seismologists say the tremors are diminishing in power, but they still pose a danger to already weakened structures.

Authorities investigating why many buildings collapsed during the initial earthquake have arrested a contractor responsible for several buildings in one of the areas worst affected by the earthquake.

The charges related to illegal building. Further arrests are expected.

The BBC's Duncan Kennedy: "The seismic shift beneath the ground has levelled much above it"

More than 48 hours after the quake struck, the official toll had risen to 2,042 dead and 6,537 injured. About 100,000 people have been left homeless.

Some 2,600 people are still missing - only nine were pulled alive from rubble on Wednesday.

But there continue to be success stories. Early on Thursday morning, about 48 hours after the first earthquake, a man was pulled alive from the rubble by a US rescue team in Yunlin county close to the quake epicentre area.

The BBC's Jill McGivering in Taiwan: "Hopes for survivors are starting to fade"

Television pictures showed the rescue elsewhere of a five-year-old girl.

"The time factor is critical at this point," US team leader Steve Catlin said.

Night of fear

The aftershocks have aggravated the plight of thousands of people made homeless by the first quake.

Most have opted to sleep in the open or in tents, fearful of returning to their damaged homes.

This family spent the night in the open

There have been more than 2,000 aftershocks since the initial earthquake, which measured 7.6 on the Richter scale, struck early on Tuesday local time.

Some have measured as high as 6.8 and have been ranked as serious quakes in their own right.

Worst-hit have been the central counties of Nantou and Taichung, where the earthquake had its epicentre and where there are few buildings still standing in some areas.

Rescue effort

International rescue teams streamed into remote areas during Wednesday, and more were on their way.

Getting into many areas - including the hard-hit Nantou town of Pu-li - has been difficult and hazardous, with roads and bridges badly damaged.

Whole sections of roads torn apart

School playing fields have been turned into makeshift airports, from where helicopters have ferried doctors, nurses and badly-needed supplies into Pu-li, as well as airlifting injured to nearby hospitals.

Taiwan has allocated three billion Taiwan dollars ($90m) for immediate relief efforts, and foreign countries have rallied with assistance.

The United Nations sent a team to co-ordinate efforts, and China - which regards Taiwan as a breakaway province - has itself offered $160,000 in cash and other help.

Hong Kong, which became a part of China in July 1997, said it was sending a 16-strong team of firemen and ambulance workers.

Turkey, which suffered its own devastating earthquake last month, has joined the United Kingdom, the United States, Russia, Switzerland, Singapore, Germany, and Japan in sending rescue experts.

France, Spain, Israel, South Korea and Thailand have also offered to help.

Worst this century

Tuesday's quake is thought to have been the strongest to hit the island this century.

Every town on the island suffered damage with Pu-li reporting 98% structural damage.

Taiwan cancelled all National Day festivities planned for 10 October, and said its stock market would stay closed until next Monday because of disruptions to power supplies.

A clear idea of the scale of economic damage may not emerge for several days.

Lavish state spending has been promised for reconstruction and the central bank has earmarked $3 billion for low-interest loans.

A BBC correspondent in Taiwan says the earthquake could disrupt the country's export industries and have a lasting impact on the economy.

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