Thirty-one US special forces and seven Afghan soldiers died when the Taliban shot down their helicopter, officials said Saturday, in the deadliest single incident for foreign troops since the war began in 2001. The Chinook helicopter was downed late Friday during an anti-Taliban operation in an insurgent-infested district of the eastern province of Wardak, just southwest of the Afghan capital Kabul. It was shot down by a Taliban rocket which completely destroyed it, the Wardak governor's spokesman said after the Taliban had claimed responsibility for the attack. The death toll was given in a statement issued by Afghan President Hamid Karzai's office and was not immediately confirmed by the NATO-led International Security Assistance Force (ISAF). "The president of the Islamic Republic of Afghanistan Hamid Karzai expressed condolences over a NATO helicopter crash and the deaths of 31 members of US special forces," the statement said. "The president of the Islamic Republic of Afghanistan expresses his sympathy and deep condolences to US President Barack Obama and the family of the victims." The statement added that seven Afghans were also killed in the crash, who the country's defence ministry confirmed were also members of the special forces. The strike was by far the worst to hit foreign troops in the near decade-long war. The previous worst saw 16 American soldiers killed in 2005 when a Taliban rocket hit their Chinook in the eastern province of Kunar. One man who said he saw Friday's shootdown, Mohammad Saber, told AFP that the helicopter plummeted during a late-night operation in his village. "At around 10:00pm last night (1730 GMT), we heard helicopters flying over us," he said. "We were at home. We saw one of the helicopters land on the roof of a house of a Taliban commander, then shooting started. "The helicopter later took off but soon after taking off it went down and crashed. There were other helicopters flying as well." Wardak provincial spokesman Shahidullah Shahid said the crash happened in Sayd Abad district during an operation against Taliban insurgents who have been waging war on pro-government forces since 2001. "The US chopper that crashed last night was shot down by the Taliban as it was taking off," he said. "A rocket fired by the insurgents hit it and completely destroyed it." He added that the helicopter had broken into several parts. A spokesman for ISAF, the foreign military force in Afghanistan, said they would issue a statement on what had happened "at an appropriate moment." Taliban spokesman Zabiullah Mujahid said the insurgent group was responsible for shooting down the helicopter, which he said was an American Chinook, and acknowledged that eight insurgents had been killed. A Western military source speaking on condition of anonymity also confirmed the helicopter type. Chinooks are widely used by coalition forces in Afghanistan for transporting large numbers of troops and supplies around the war zone. The crash takes the total number of foreign troops killed in Afghanistan this year to 342, according to an AFP tally based on that kept by independent website iCasualties.org. Of those, 279 were from the US. There are currently about 140,000 foreign troops in Afghanistan, around 100,000 of them from the United States, fighting as part of the international force that has been in the country for almost 10 years. Some troop withdrawals have already begun as part of a process which is due to see all foreign combat forces leave the country by the end of 2014. However, the Taliban are still waging a bloody insurgency in the country. In recent weeks, a string of high-profile figures close to Karzai have been assassinated. US special forces play a key role in the war against the Taliban and other insurgents by hunting down and killing high-profile fighters in targeted raids. Foreign troop commanders say the east of Afghanistan, which borders Pakistan where insurgents have hideouts, will likely increasingly overtake the south as the focus of the war in coming months.