At least 4 people were shot dead and several wounded on Saturday as police opened fire at workers demanding a pay rise at a Chinese-backed coal-fired power plant in southeastern Bangladesh, police reported.

Police were obliged to open fire when demonstrators assaulted them at the under-construction power plant in Chittagong, local police official Azizul Islam told Reuters 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 key source of foreign investment into Bangladesh, and one of a series of projects Beijing is pushing to cultivate closer relations with Dhaka.

In 2016, China’s SEPCOIII Electric Power Construction signed a deal with S Alam Group, a Bangladeshi conglomerate responsible for building construction at the site.

That year, four protesters opposing its construction were killed after villagers for and against the power plant clashed before riot police opened fire after coming under attack.