The hundreds of thousands of people who live in one of Africa's largest slums are suffering new hardship after police cut electricity and water as they try to crack down on criminal gangs. As Nick Wadhams reports from our East Africa bureau, the campaign has increased the dangers faced by women and children in the slum.

Police say a criminal gang called the Mungiki was profiting off illegal water and power connections in Mathare, which is home to about 500,000 people. The move against the gang was part of a wider crackdown in which police have killed dozens of people, destroyed some homes, and arrested hundreds.

Kenyan authorities have drawn accusations that their campaign is heavy-handed and indiscriminate and that most of the arrested have nothing to do with the Mungiki. Police say the group has killed at least 27 civilians and 15 police since April.

After power was cut on Thursday, social workers said the people who would suffer most would be women and children. Agnes Musau is a program officer with the Child Welfare Society, which looks after children in Mathare.

"Most of them are extremely, extremely poor. In fact, what happens, some of them go to learn with the electricity borrowed from others," said Musau. "You know they move to one house where that family can afford electricity, they sit as a group, they are able to read, they are able to do their homework, then they can go back to their houses, that is one person benefiting the others. So to me it has an impact on the child's right to education."

The electricity cutoff came after police clashed with residents in the slum earlier on Thursday. People threw stones at police, who fired into the air. Several residents were arrested.

Musau and others in Mathare believe the police crackdown is politically motivated. Kenya is expected to hold elections later this year, when President Mwai Kibaki will seek a second term. Some members of the Mungiki have reportedly threatened to disrupt the vote.

Musau says the decision to cut electricity to parts of the slum will encourage what she says is a largely hidden threat to children there: sexual abuse.

"In Mathare, I would say it is silent thing, but most of the children especially the bigger ones between 10 and 15 years, if you go through, most of these children have been silently sexually abused," said Musau. "Now if they move from those houses, what protection are they exposed to? What protection?"

An estimated 60 percent of Nairobi's three million people live in slums. Mathare sits just two miles from Nairobi's city center. Hundreds of people fled the slum late last year during clashes between the Mungiki and a rival gang, known as the Taliban, which is not related to the militant group in Afghanistan. Several people were reported killed.