RANCHI, India  - Indian Maoist rebels have shot dead seven policemen in the eastern state of Jharkhand, a hotbed of left-wing extremism, police said on Tuesday.Acting on a tip-off by state intelligence authorities on Monday, local police headed towards Latehar district, 108 kilometers from the state capital Ranchi, to arrest suspected Maoists who were meeting in a forested area.“Our teams rushed to the meeting spot and a gunfight erupted between the rebels and police,” Jharkhand’s top police officer GS Rath told AFP.“Seven policemen were killed and 13 were injured by over 100 rebels involved in this attack,” he said. Maoists say they are fighting for the rights of poor farmers and landless labourers. They have spread into rural pockets in 20 of 28 states.Thousands have been killed in the insurgency since the late 1960s. The Indian government describes the guerrillas as the country’s most serious internal security threat.