The number of people forced into slavery around the world has risen to 27 million, according to a report published by an international human rights group.

The study - released to coincide with a special UN session on slavery - says millions of girls working as domestic servants are forced into sexual slavery.

The trafficking of child camel jockeys to the United Arab Emirates, bonded labour in Pakistan and forced labour in Sudan are also highlighted.

Slavery is fuelled by "poverty, vulnerability and lack of political will", Anti-Slavery International says.

Forced labour

Last week, the US endorsed a report drawn up by an international group of "eminent persons" which concluded that slavery existed in Sudan.

Slavery

Sudan: Between 5,000 and 14,000 abducted since 1983 Millions of girls forced into domestic service worldwide Hundreds of boys trafficked to the Gulf to race camels (Source: Anti-Slavery International)

The report recommended that the Sudanese President, Omar Hassan al-Bashir, take the lead by launching an anti-slavery campaign and calling for the release of all slaves.

The Sudanese Government comes in for criticism from Anti-Slavery International, which accuses it of "failing to take adequate steps to end raiding and slavery".

Between 5,000 and 14,000 people are said by the group to have been abducted into forced labour in Sudan since 1983.

There are also problems of forced labour in Mauritania where, the London-based rights group says, little has been done to secure the release of slaves or punish those who use them despite the abolition of slavery in 1981.

In Brazil, the report says, more than 1,000 people were rescued from forced labour last year, but many more remain enslaved on Amazonian estates.

The report says that in Pakistan, particularly in Sindh province, many women, children and men are forced to accept landlords' cash advances and work all day long for no wages.

Sex work

Many of those who are forcibly employed across the world are children.

Anti-slavery activists say millions of girls working as domestic servants are denied freedom and education and are vulnerable to abuse. Many are forced into sex work.

Boys are also victims. The report estimates that every year hundreds of boys, aged between four and 10, are trafficked from South Asia to the United Arab Emirates and other Gulf states to race camels, a dangerous sport.