A total of 11 people including four NATO and three U.S. soldiers were killed Thursday when a NATO military helicopter crashed in restive southern Afghanistan, the NATO said in a statement. "An ISAF helicopter crashed in southern Afghanistan today. The crash resulted in the deaths of four International Security Assistance Force (ISAF) service members, three United States Forces-Afghanistan service members, three members of the Afghan National Security Forces (ANSF), and one Afghan civilian interpreter," the NATO-led ISAF said in the statement. The ISAF statement did not provide details about the incident, only saying "The cause of the crash is under investigation." The statement also did not reveal information about the casualties. "It is ISAF policy to defer casualty identification procedures to the relevant national authorities." Meantime, an Afghan official said that the helicopter was crashed in southern Kandahar province. "The helicopter went down in Chinarto area of Shah Wali Kot district in Kandahar province during a military operation," a provincial official Jawid Faisal told Xinhua without giving the exact time of the incident. The Taliban-led insurgency has been rampant since the militant group launched an annual spring offensive dubbed "Al-Farooq" from May 3 against Afghan and NATO-led troops stationed in the country. Furthermore, a Taliban purported spokesman, Qari Yousuf Ahmadi claimed that Taliban insurgent fighters shot down a U.S. helicopter, killing all people aboard in Kandahar province. Up to eight U.S. and NATO military helicopters have crashed so far in 2012, killing at least 28 service members while more than 290 U.S. and NATO soldiers have been killed across Afghanistan since the beginning this year.