By Ruma Paul DHAKA, April 17 (Reuters) - At least four people were shot dead and many injured on Saturday as police opened fire at workers demanding a pay rise at a Chinese-backed coal-fired power plant in southeastern Bangladesh, police said. Police were forced to open fire when protesters attacked them at the under-construction power plant in Chittagong, local police official Azizul Islam told Reuters by from the location. "Four died and many injured... We're trying to control the situation," Islam said, adding that at least six police personnel were also among the injured. The $2.4-billion power plant, located 265 km (165 miles) southeast of the capital Dhaka, is a major source of foreign investment into Bangladesh, and one of a series of projects Beijing is pushing to cultivate closer ties with Dhaka.