By Nityanand ShuklaRANCHI, India, April 22 (Reuters) - Maoist rebels, some armed with bows and arrows, briefly hijacked a train with around 500 passengers in eastern India on Wednesday in a show of strength on the eve of the second stage of India's general election.About 300 Maoists boarded the train and forced the driver at gunpoint to take it to Latehar station in a remote area around 160 km (100 miles) west of Ranchi, the capital of Jharkhand state, before they fled four hours later."All the passengers have been released and they are safe," Sarvendu Tathagat, a local government official in Jharkhand, said. "They (the rebels) left the train and fled into the jungles."India's Maoist rebels, who say they are fighting for the rights of landless labourers and poor farmers, have stepped up attacks in their strongholds in central and eastern India during the election.Rebels have called a strike in the region to protest the killing of some villagers branded as Maoist supporters by police.Prime Minister Manmohan Singh has described Maoist violence as India's biggest internal security threat. Some 500 civilians and police were killed in insurgent clashes last year.Maoists have taken over trains in past years in a show of strength, often holding them up for several hours. In 2006, a train was hijacked in Latehar and the 200 people onboard were released unharmed after one night.Maoist rebel violence marred the first stage of India's election last Thursday when five election officials were killed in a landmine blast in Chhattisgarh state. Eleven police were killed across the central and eastern "red belt".Thousands have been killed in the Maoist insurgency which began in the late 1960s and now stretches throughout rural areas of eastern, central and southern India.In separate attacks, Maoist rebels blew up a railway station in Jharkhand on Tuesday, disrupting train services. They also blasted a health centre and a school building.Maoists also carried out scattered attacks on Wednesday, shooting dead a truck driver and torched eight trucks and oil tankers in the eastern state of Bihar.India is holding a staggered general election over April and May in which 714 million people are eligible to vote. (Editing by Alistair Scrutton and Dean Yates)