The two separate cases have fuelled a debate about how children are raised in the country.

A 31-year-old single mother was placed in psychiatric care after her five sons, between three and nine years old, were found dead in her house in the small northern town of Darry, near Kiel, on Wednesday.

The grim discovery came hours after police announced the arrest of an unemployed 28-year-old mother suspected of having killed three of her young children in Plauen in the eastern state of Saxony.

Police commissioner Juergen Boerner told N-TV television yesterday of the mother in the Darry case: 'We think she gave them tranquillisers and then suffocated them with plastic bags.

'We think the motive for the killing could be found in the mother's psychiatric illness.'

As police searched for evidence, visibly upset neighbours gathered yesterday at the spacious brown-brick home where the children were found.

'I hope they did not suffer too much,' said a crying 64-year-old resident.

The neighbours said the family had moved to the town, which has fewer than 500 residents, about three months ago.

According to the local press, the bodies were found after welfare officials went to the house because the children had been absent from school. Their teachers had reportedly remarked that the boys looked neglected and went to school without wearing winter coats.

In Plauen, police said they had detained the woman after finding a baby's body in a suitcase in her apartment cellar a week ago but released her after failing to find evidence that the child had died violently.

She was rearrested after they discovered two more bodies wrapped in plastic on the balcony and in the fridge.

The female children were born in 2002, 2004 and 2005. Autopsies are being carried out to establish the causes of death.

Prosecutor Bernd Vogel said there were no clear signs that the children had died violently but added: 'It is highly improbable that they all died of natural causes directly after birth.'

The woman has two sons and has denied killing the girls.

The fate of the babies brings to mind the country's worst post-war infanticide case, in which an unemployed woman suffering from cancer was sentenced to 15 years in jail last year for manslaughter, for having left eight newborn babies to die.

Police found their remains hidden in buckets and flowerpots in which the woman had planted vegetables.

Last month, a 35-year-old woman from Erfurt, central Germany, was jailed for 12 years for killing two babies and hiding the bodies in a freezer.

The on-going debate about the plight of children in impoverished families intensified last month when a five-year-old, identified only as Lea-Sophie, died of starvation. Her parents are facing murder charges.

Her death sparked calls for children's rights to be enshrined in the Constitution to stem the tide of abuse cases.

German Chancellor Angela Merkel expressed shock at the plight of Lea-Sophie, who had weighed 7.4kg when she died - less than half the weight of a healthy five-year-old.

The independent welfare organisation Deutsche Kinderhilfe Direkt said yesterday that the deaths of the eight children this week 'are not regrettable isolated cases' but point to 'a crisis' in German society.

'We live in a society where nobody looks around them and where children are not cherished,' its chairman Georg Ehrmann told Bayerische Rundfunk radio.

AGENCE FRANCE-PRESSE