Turkish authorities have declared a new 24-hour, indefinite curfew at a mainly-Kurdish town where Turkey's security forces are set to launch a large-scale operation to battle Kurdish militants.

The local governor's office said the curfew would take effect in the town of Yuksekova — near Turkey's borders with Iraq and Iran — at 2000 GMT on Sunday. It said entering and leaving the town would also be banned. News reports say dozens of tanks have been deployed to Yuksekova.

Turkey has imposed curfews in several flashpoint districts in the southeast since August to root out militants linked to the Kurdistan Workers' Party, or PKK, who had set up barricades, dug trenches and planted explosives.

The military operations have raised concerns over human rights violations and scores of civilian deaths.