Image copyright Getty Images Image caption A rescued child boards a train that will take him back to his family in Bihar

Hundreds of children, forced to work in "inhuman conditions", have been rescued from factories in southern India.

At least 350 children were removed during raids on leather tanning and plastic workshops in Hyderabad, over a 10-day period.

They were working long hours in deplorable surroundings, police said.

Widespread poverty and lack of education result in many children being pushed into work. Sometimes their wages may be promised to their parents.

The authorities said five men had been accused of supplying the young people to factory owners.

Child welfare officials accompanied some of the children on Thursday as they were reunited with their parents in Bihar, one of India's poorest states.

Nearly 200 others travelled back to Bihar in northern India earlier in the week, police said.

Monitored by cameras

Police official V Satyanarayana revealed several of the rescued children were suffering from skin problems and other diseases.

He said: "We found the children confined to their work place in inhuman conditions.

"They were forced to work for nearly 12 hours a day without any respite."

He said the children were kept in unhygienic and unventilated dark rooms and monitored by their employers using video cameras.

Any child who stopped working would be beaten, he said.

Image copyright Getty Images Image caption Many of the rescued child workers were reunited with their parents

Image copyright Getty Images Image caption Some of the rescued children were suffering from health problems

Image copyright AP Image caption Indian officials estimate that more than four million children illegally work in factories

India has laws aimed at fighting child labour, including compulsory education up to the age of 14.

In 2012 the employment of children under the age of 14 became illegal - thanks in part to the work of activist Kailash Satyarthi who won the Nobel Peace Prize for his work in 2014.

He has long campaigned against child labour and rescued children from servitude

But India still has millions of child workers - a 2011 census put the number at about 4.35 million. Mr Satyarthi says it is as high as 60 million.

Many parents say poverty forces them to send their children to work in other people's homes or in factories.

Others are kidnapped from their families and trafficked to different regions. One child goes missing every eight minutes in India and nearly half of them are never found.

A labour welfare official said raids on factories to check for child workers will now be carried out twice a month.

RV Chandravan added: "We are taking effective measures to eradicate the mafia behind bringing children from other states to work in hazardous industries in Hyderabad."