NEW DELHI, May 24 (Xinhua) -- The death toll from firing on anti-Sterlite protests in southern Indian state of Tamil Nadu on Thursday rose to 13, officials said.

"One more person who was wounded in firing on Tuesday has succumbed today morning," an official said.

On Tuesday, 11 persons, including two women were killed in firing on protestors demanding closure of Sterlite Copper Smelter, near Thuthukkudi, while as one more person was killed on Wednesday.

Security has been beefed up in Thuthukudi.

According to India's official broadcaster, All India Radio (AIR), internet-based services in Thuthukudi and neighbouring districts of Kanniyakumari and Tirunelveli have been cancelled since Wednesday evening.

The state's opposition parties including DMK have called for a shutdown on Friday against police firing on protesters.