A series of aftershocks rattled New Zealand's quake-devastated city of Christchurch again today.
Bricks came crashing down in the cordoned-off city centre, where only workers have tread since it was devastated in February's major earthquake. About 200 people were there when the quakes struck - two were briefly trapped in a church.
In all, 10 people were injured in the city.
"This has been a setback for Christchurch and its people, but it does not lessen our resolve to rebuild," said Prime Minister John Key.
"The people of Christchurch should know all New Zealanders are thinking of them and will continue to support and stand by them in this very difficult time."
Across the city, people fled buildings in panic when a 5.2-magnitude quake struck during lunch time; just over an hour later, a 6.0-magnitude hit, according to the US Geological Survey. Other smaller quakes were also recorded.
In the central city and nearby suburbs, several buildings were damaged.
"We are being enveloped with dust," said Christchurch Mayor Bob Parker. "It is very, very scary."
The city has been shaken by thousands of aftershocks since the 6.3-magnitude quake killed 181 people on February 22. Like that tremor, today's two biggest quakes were very shallow, both around six miles deep.
The shallow depth of the February quake and its proximity to the city helped magnify its destructive force.
About 47,000 homes in the city's eastern suburbs were left without power after the latest aftershocks when temperatures were expected to approach freezing. Rocks tumbled down hills in the area, which was among the hardest hit in February, and slit bubbled up from the earth - a process known as liquefaction that sometimes happens during a quake.
After the February quake, 300,000 tons of silt had to be scraped away, and the silt alone made thousands of homes uninhabitable.
Roger Sutton, chief executive of the Canterbury Earthquake Recovery Authority, said the extra damage to the city centre means that some buildings that had been salvageable "are now seriously damaged and will have to be brought down".
The group's demolition manager "was driving (during the 6.0 quake), and there were buildings coming down in front of him, coming down behind him," Sutton said. "He's very lucky to be alive."
More than 40 people have been taken to hospitals with minor injuries from falling debris, the city council said. Two of them were salvaging windows from St John's Church when the building's facade, the last wall standing after February's quake, collapsed. Police said they were rescued and taken to a hospital with cuts and bruises.
Another building nearby fell, according to police, and the dean of the city's cathedral said the collapsed building suffered new damage.