New Delhi - Five police were killed and three injured Saturday in an eight-hour-long gunbattle with Maoist rebels in eastern Indian state Jharkhand, about 20 kilometres from where Congress Party president Sonia Gandhi addressed an election rally. Maoist rebels, who operate in 13 of India's 29 states, have increased attacks on government installations in the run-up to the general elections which are scheduled to begin Thursday.

"Five CRPF (Central Reserve Police Force) personnel were killed and three were injured in an ambush by Maoist rebels in Khuti district," IANS news agency quoted Jharkhand Police spokesman SN Pradhan as saying.

Police said the gunbattle at Musanga Jorpa jungle, about 70 kilometres south of Jharkhand capital Ranchi, began Saturday morning and ended at around noon a little before Sonia Gandhi addressed a rally in the area,

Paramilitary forces patrolling the area ahead of Gandhi's arrival came upon a group of Maoist rebels. When asked to surrender, the rebels fired and the gunbattle followed.

Maoist rebels have blown up 11 government buildings in Palamau, Latehar, Garwah, Gumla, Chatra and Bokaro districts of the state over the past week. Their targets have included schools, village-level government offices and pre-school centres.

The string of attacks is aimed at preventing security personnel from staying in these buildings during elections, IANS quoted a police source as saying.

Two-phased parliamentary elections are scheduled to be held in Jharkhand on Thursday and April 23.

On Friday, nine CRPF troopers, including an officer, were killed in an attack by another group of about 100 armed Maoist rebels in Bastar district of neighbouring Chhattisgarh state.

Chhattisgarh is also scheduled to go to the hustings on Thursday, the first day of voting in India's month-long five-phase elections.

Maoist rebels have asked people to boycott the elections.

According to independent estimates, more than 600 people including civilians, police and rebels were killed in Maoist violence in India in 2008.

Prime Minister Manmohan Singh has described the Maoist insurgency as one of the gravest internal security threats facing India. (dpa)