Benghazi, Libya (CNN) -- Rebel forces in the Nafusa Mountains of western Libya were under heavy attack Tuesday by forces loyal to leader Moammar Gadhafi and had issued a call for help, the National Transitional Council said. "Representatives have confirmed that Gadhafi forces are using GRAD missiles, snipers, and a previously unseen type of mortar," it said, adding that three locals were killed and another nine wounded on Tuesday.