GUWAHATI, India, Jan 6 (Reuters) - Separatist rebels in India's restive northeastern state of Assam shot dead 16 people, mostly labourers and traders, in coordinated overnight attacks, police said on Saturday. United Liberation Front of Asom (ULFA) guerrillas carried out the attacks in the state's eastern districts of Tinsukia, Didrugarh and Sivasagar. The rebels gunned down eight traders in a crowded market in Tinsukia's Doomduma town, police said, adding that seven labourers were also killed in two separate strikes in Dibrugarh district. "There were about 10 militants in each group and they attacked the labourers when they were preparing their dinner," V.K. Ramisetti, a senior police official in Dibrugarh, said. Another person was killed when militants triggered a blast in Sivasagar. Police said the violence was an attempt to create an atmosphere of fear after an opinion poll by an NGO in nine districts of the oil-and-tea rich state showed 90 percent of the people rejected ULFA's separatist demands. The three districts that witnessed the attacks had not been polled. The attacks also came a day after Indian officials appealed to the ULFA not to disrupt national games next month which the rebels have threatened to stop with violence. The insurgency in Assam has killed more than 20,000 people since it began in 1979.