Kathmandu - Police have fired into a crowd of demonstrators in Nepal, killing one, as the country prepares to adopt a controversial new constitution.

The new charter, aimed at cementing Nepal's transformation from Hindu monarchy to secular democracy, will come into force later on Sunday.

Authorities said the fatality occurred in the southern district of Parsa when police opened fire on a crowd of demonstrators after thousands of Madhesi demonstrators defied a curfew.

"One person was killed when the police were forced to fire after thousands came out in the street defying the curfew," Kesheb Raj Ghimire, Parsa's chief district officer, told AFP news agency by phone.

"They attacked with stones and glass bottles. Some of the security forces have been injured as well as the demonstrators. The situation here is tense."

Legislators here in Kathmandu, the capital, adopted the bill on Wednesday despite weeks of violent protests that left more than 40 people dead, among them two children and a police officer who was lynched as he was driven to hospital in an ambulance.

The new constitution will divide the Himalayan nation of 28 million people into seven federal provinces, a move aimed at devolving power from the centre.

However, some historically marginalised groups say the division will leave them under-represented in parliament.

Source: Al Jazeera and agencies