A strong aftershock has hit northern Algeria where an earthquake last week left more than 2,000 dead and thousands more injured and homeless.
A 15-storey building collapsed in Reghaia trapping several people
The latest tremor, with a magnitude of up to 5.8, caused widespread panic, with residents running into the streets as buildings swayed and in some cases collapsed.
At least 200 people were reported injured by state television in Algiers and also Boumerdes - one of the cities worst hit by last week's quake - and there were unconfirmed reports of further deaths.
"Families rushed out of buildings. Everyone took to the streets. In central Algiers people were scared, real scared, holding their children and babies in their arms," a Reuters correspondent in the city said.
A worker for the International Red Crescent in the area, Christopher Black, told the BBC that the psychological damage on the already traumatised population would be immense.
The new tremor's epicentre appeared to have been in Zemmouri, around 30 miles (50 km) east of the capital, Algiers and close to the epicentre of last Wednesday's earthquake.
22 December 1999: 28 dead and 175 injured in north-west
18 August 1994: 172 dead and 288 injured in western region of
29 October 1989: 30 dead and 400 injured in Tipaza region
10 October 1980: About 3,000 dead and 8,000 injured and in al-Asnam
9 and 16 September 1954: 1,400 dead and 14,000
"There is general panic, damaged buildings are collapsing," Muhammad Saidi, a local doctor in Boumerdes told French news agency AFP.
"People are running around, people are panicking. I put myself
in God's hands," another man said.
There were reports of up to nine people being trapped under a 15-storey building that collapsed in the town of Reghaia.
"One person is probably still alive but (she) is very deep in the building and is unfortunately starting to cough," said the leader of a French rescue team at the site.
Earlier, deputy Interior Minister Mohamed Guendil had said three people might have been killed in the building, which was badly
damaged by last week's quake.
The earthquake which struck last Wednesday killed at least 2,218 people and injured more than 9,000.
The death toll could end up much higher, with Algerian newspapers reporting as many as 2,000 people still unaccounted for.
Fear of disease
Following last week's disaster health and aid workers have stepped up relief efforts in the quake zone, fanning out across the region to prevent outbreaks of diseases like cholera.
Hundreds of people are still missing from last week
Medics said so far there were no signs of diarrhoea epidemics among the population, but there was a risk they would flare up in the makeshift camps many residents have been forced to live in after their houses were destroyed.
The Algerian Red Crescent has estimated that up to 100,000 people are still too afraid to return to their homes, although the Algerian Government puts the figure at closer to 10,000, AFP reported.
Efforts to find survivors have wound down after workers said there was little chance that anyone remained alive in the buildings crumpled in last week's quake, and many international teams of rescuers have begun to return home.