UPDATE 1-Boy killed in India violence, Mumbai leader free

(Recasts with violence, adds politician bailed)

By Rina Chandran

MUMBAI, Oct 22 (Reuters) - A 10-year-old boy was killed when police opened fire on protesters in eastern India on Wednesday, officials said, as rioters set trains alight and blocked roads in retaliation for attacks on migrants in the west of the country.

The child was hit by a stray bullet and died at the scene after police in Rohtas district, in the eastern state of Bihar, fired on a mob attacking a train station, Naval Kishore Mishra, a police officer, said from Rohtas.

At least six people and several policemen were injured when rioters threw stones and clashed with police, he said.

The migration of thousands of workers from impoverished northern and eastern states such as Uttar Pradesh and Bihar into India's booming financial capital Mumbai has sparked a violent backlash, with local resentment fuelled by ambitious politicians.

That in turn has provoked tit-for-tat violence in northern and eastern India, a sign of the strains that inequality is placing on society as parts of the country's economy booms.

On Wednesday, a local politician, whose arrest sparked violent protests in Mumbai was given bail after spending a night in jail.

Raj Thackeray, head of the small but vocal Maharashtra Navnirman Sena (MNS) party, was arrested on Tuesday for rioting and provoking attacks on migrants.