Federal police in India have arrested 12 people on charges of murder and gang rape during the 2002 Gujarat riots.
The riots left at least 1,000 dead - mostly Muslims
Officers of the Central Bureau of Investigation (CBI) arrested them on Wednesday in the state's Dahod district late on Wednesday.
More than a thousand people, mainly Muslims, were killed in the riots.
The CBI was asked to take over the investigations by the Indian Supreme Court because their poor handling by local police.
The Gujarat riots were India's worst religious violence for a decade.
A team of CBI officers had been carrying out investigations in Dahod over the past 20 days and started making arrests on Wednesday night.
The accused are to be produced in a local court later on Thursday.
They face charges in connection with an attack on a Muslim group by a Hindu mob in March 2002.
The CBI was asked to follow up the case after India's National Human Rights Commission came in support of the petitioner and a key eyewitness, Bilkis Bano.
Bilkis Bano, who was pregnant at the time, is reported to have seen three women being raped in the incident in which 14 Muslims were also killed.
Ms Bano herself managed to survive because the attackers assumed her to be dead.
She says she had named the accused to the Gujarat police but they allegedly took no action.
Later she approached the National Human Rights Commission which supported her petition in the Supreme Court.
The Gujarat riots started after 59 Hindus were killed in an attack on a train carrying Hindu pilgrims in February 2002. That attack was blamed on a Muslim mob.
Nearly 1,000 people, mainly Muslims, were killed in clashes that followed according to the Gujarat state government's figures.
Other estimates put the toll at 2,000.
The Gujarat authorities have been criticised for their poor handling of riot cases.
Last October, the Supreme Court ordered the government to appoint new public prosecutors to handle the cases following the acquittal of 21 Hindus charged with burning 12 Muslims in a bakery in Baroda city.