An official says protesters demanding statehood in western Nepal attacked police enforcing a curfew, killing at least six officers and wounding many more.

Government Administrator Raj Kumar Shrestha said at least three protesters also were killed in the violent clash at Tikapur town.

The thousands of protesters attacked the officers with spears, knives and stones.

The wounded have been taken to the regional hospital and the death toll is expected to rise.

Additional police forces from neighboring districts have been rushed to the town.

The protesters from the Tharu ethnic group are demanding a separate federal state for them in the new constitution, which is being given final touches in the Constituent Assembly.