New Delhi  - Suspected Maoist rebels shot dead two senior officials of a coal mine, torched trucks and blew up railway tracks in India's eastern Jharkhand state Monday, on the first day of a general strike in the region, officials and news reports said.

The deputy director and the assistant director of the private Panam coal mine were killed by unidentified assailants when the officials were taking a morning walk near the facility in Pakur district, the NDTV network reported.

Although police claimed it was a criminal activity and not a Maoist attack, district administration officials told the news channel that the killings were done by Maoist militants.

Guerrillas have killed a police inspector, a bank manager and engineer in the state in recent days.

The rebels also blew up railway tracks in the central Bokaro district, and train services on the route were suspended, police said.

The rebels called a two-day shutdown in Jharkhand and neighbouring Bihar state to protest the Indian government's crackdown. The strike is also to protest the alleged police repression of villagers in the name of counterinsurgency.

Government troops have already launched an offensive against the Maoists in the central state of Chhattisgarh as well as the western state of Maharashtra where they killed 18 policemen in an ambush last week.

Elsewhere in Jharkhand, the Maoists carried out violent attacks, setting ablaze four trucks and blowing up a bridge in the Girdih and Dhanbad districts. They also fired indiscriminately at buses injuring three people.

Local news outlets reported that the insurgents had also blown up mobile phone towers in the state and were felling trees to block highways.

The violence in Jharkhand comes a day after Indian Prime Minister Manmohan Singh termed the Maoist insurgency as the "greatest internal security threat" to the country.

The rebels, who say they are leading an armed rebellion to secure the rights of the poor and marginalized, operate in 20 of India's 28 states.

They are against the democratic process and call for a boycott of elections. The rebels usually target security personnel and government installations and officials.

At least 2,671 people - including civilians, security personnel and rebels - have been killed in incidents related to Maoist violence in India since 2006, according to federal Home Ministry data. (dpa)