The death toll in the Chilean earthquake rose to more than 700 last night as rescue workers struggled to find survivors trapped in the wreckage and powerful aftershocks battered the country. About 350 deaths were in the holiday resort of Constitución, and scores of tourists remain on the missing list.

President Bachelet said that 708 people had been confirmed as dead in “a catastrophe of such unthinkable magnitude that it will require a giant effort for Chile to recover”.

The army have been brought in help the police against looters and would take control of Concepción, the country’s second largest city. The Government would start to distribute food and water today.

As the first reports emerged from coastal towns, it became clear that they had suffered the heaviest damage after Saturday’s 8.8-magnitude earthquake, because they were also struck by the tsunami that followed.

Tens of thousands of Chileans will spend another night in tents and makeshift shelters, fearing aftershocks would destroy more buildings.

Rescue operations have been hampered by the aftershocks, with more than 90 registered across the country in the 24 hours after the earthquake. The strongest reached 6.9 on the Richter scale.

The earthquake had an impact from the desert region of Antofagasta, in the north, to the Lakes region in the country’s southern tip. Few parts were untouched, with an estimated two million people affected and 1.5 million homes and buildings destroyed or badly damaged.

The earthquake was felt as far away as São Paulo in Brazil, 1,800 miles to the northeast. Experts said that it was hundreds of times more powerful than that which hit Haiti in January.

Chile is one of South America’s wealthiest nations and is well prepared for earthquakes, with modern buildings designed to withstand the regular seismic activity in the region.

Offers of aid poured in from the international community. Hillary Clinton, the US Secretary of State, is to visit today as part of a scheduled regional tour. Britain, one of Chile’s biggest trade partners, said that it was ready to help. Gordon Brown said: “We will do whatever we can.”