(Adds anti-Sanlu website blocked, paragraph 6)
BEIJING, Jan 2 (Reuters) - A group of parents whose children fell ill from drinking tainted Chinese milk have been detained by police apparently trying to block them from holding a news conference, one of the fathers said on Friday.
At least six children have died from kidney stones and more than 290,000 been made ill from the melamine-contaminated milk, battering already dented faith in China-made products and prompting massive recalls around the world.
Tian Wenhua, the 66-year-old former general manager of the now bankrupt Sanlu Group, pleaded guilty on Wednesday to charges of "producing and selling fake or substandard products". She is expected to be sentenced to life imprisonment, the Beijing News said.
One of the fathers, whose 13-month-old son suffers from severe kidney stones, said some parents, including himself, were taken to a labour camp on the outskirts of Beijing.
"We are under house arrest now, and they did not give us any reasons why they kept us here," the father told Reuters by phone.
Five parents had been detained, but the rest of the group held a news conference on Friday, calling attention to the plight of the children. A website created by anti-Sanlu protesters was blocked on Friday. It was not immediately clear why.
"The government said all the medical care is free, but when it comes to the local level, things change. I have already paid more than 50,000 yuan ($7,300) for the operation and cure," said the father, a migrant worker from Sichuan province.
Melamine, an industrial compound used in plastic and fertiliser, was added to milk to cheat protein tests.
Some 22 dairy firms, led by Sanlu, have apologised and asked forgiveness for the contamination.
"We are deeply sorry for the harm caused to the children and society," they said in a New Year text message to millions of phone subscribers. "We sincerely apologise for that and we beg your forgiveness." (Reporting by Reuters Television; Editing by Nick Macfie and Alex Richardson)