American service personnel in Afghanistan are dying at a rate of about one per day so far this year despite a drawdown of troops. That death rate has risen recently with the summer fighting season in full gear and a rash of attacks by Afghan security forces on their foreign trainers and partners.
NATO forces said they could not confirm what caused Thursday's crash and stressed that it was still being investigated. The Black Hawk was operating in support of an ongoing assault on the ground but initial indications were that it was not shot down, according to U.S. officials who spoke anonymously because the investigation was continuing.
Taliban spokesman Qari Yousef Ahmadi said insurgent fighters struck the helicopter in Kandahar province on Thursday morning. He declined to give further details in a phone call with The Associated Press.
The Kandahar provincial government backed the Taliban claim. It said the helicopter was shot down in Shah Wali Kot district, a rural area north of Kandahar city where insurgents move freely and regularly launch attacks. Provincial spokesman Ahmad Jawed Faisal did not provide details or say how the province had confirmed the information.
Kandahar is a traditional Taliban stronghold and the spiritual birthplace of the hardline Islamist movement, which ruled Afghanistan before being ousted in 2001 by the U.S.-led alliance for sheltering al-Qaida's leaders.
Thursday's crash came less than a week after six American service members were gunned down, apparently by two members of the Afghan security forces they were training to take over the fight against the insurgency.
White House spokesman Jay Carney said Thursday that the U.S. is prioritizing efforts to prevent more of these types of attacks. NATO says that 34 international service members have been killed in attacks by Afghan security forces or militants wearing their uniforms so far this year.
The international force "is continually assessing and refining procedures in force protection so that we can both meet mission requirements and ensure the safety of our forces," Carney said.
The Taliban said Thursday that the insider attacks are part of a strategy to undercut the alliance between the Afghan government and international forces.
"Mujahideen have cleverly infiltrated the ranks of the enemy according to the plan given to them last year," the militants said in their annual statement ahead of the Eid al-Fitr holiday marking the end of Ramadan, the Muslim holy month.
The attacks on U.S. service personnel have stirred fresh doubts about the capability of Afghan security forces to secure the country in less than two years' time. The majority of international combat troops are scheduled to exit the country by the end of 2014.
With Thursday's crash, at least 26 Americans have been killed so far this month and at least 219 so far this year.
That adds up to fewer deaths than in 2011, when 233 U.S. service personnel had died by the end of July. But more than 100,000 U.S. forces were stationed in the country a year ago, and thousands of those have already left as part of the drawdown ordered by President Barack Obama. The military hopes to trim the force to 68,000 troops in Afghanistan by October.
The Taliban, meanwhile, are not laying low. Insurgent attacks were up 11 percent in the three months of April through June compared with the same period of 2011, according to NATO. And the U.N. reported last week that targeted killings of civilians were surging. Afghan police and army casualties have also been on the rise.
And July has been the deadliest month of 2012 for U.S. troops, with 40 killed as a result of war-related violence - slightly more than in the same month of 2011.
But back home, Americans appear to be paying less attention to the war.
Afghanistan has rarely come up in the presidential campaign as Obama and Republican challenger Mitt Romney focus on the economy, jobs and taxes as the key issues. Romney, a one-term Massachusetts governor who spent most of his career in the private sector, has said he disagrees with Obama's timing to bring the last combat troops home at the end of 2014 but has offered few details of how he would change it.
As U.S. forces decrease in Afghanistan, much more of the war is likely to be fought in the shadows by elite forces who issue few press releases or statements about their strategy. Three of the seven U.S. service personnel killed in Thursday's crash were special operations forces - two Navy SEALS and a Navy explosives expert, U.S. officials said on condition of anonymity because they were not authorized to disclose the information.
The crash killed all of those aboard - seven U.S. troops, three members of the Afghan security forces and an Afghan civilian interpreter, said Jamie Graybeal, a spokesman for the coalition.
The downed helicopter was a Sikorsky UH-60 Black Hawk, a medium-lift helicopter that has served as the U.S. Army's workhorse since the 1980s.
The U.S.-led NATO force in Afghanistan has relied heavily on utility helicopters such as the Black Hawk to ferry troops, dignitaries and supplies around the mountainous terrain, thus avoiding the threat of ambushes and roadside bombs.
Thursday's crash was the deadliest since a Turkish helicopter struck a house near the Afghan capital, Kabul, on March 16, killing 12 Turkish soldiers on board and four Afghan civilians on the ground, officials said. In August 2011, insurgents shot down a Chinook helicopter, killing 30 American troops, mostly elite Navy SEALs, in Wardak province in central Afghanistan.
At least 1,961 U.S. service personnel have been killed in Afghanistan over the course of the 11-year war.
Casualties have jumped each year in the summer, when warm weather makes it easier for insurgents to move through mountain passes and carry out attacks. The three deadliest months of the war for U.S. troops have been in summer: August 2011, 71 deaths; July 2010, 65 deaths; June 2010, 60 deaths. During the winter, the Taliban and other insurgent groups have tended to bed down to wait out the cold.
Associated Press writers Lolita C. Baldor in Washington, Slobodan Lekic in Brussels, Mirwais Khan in Kandahar, Afghanistan, and Amir Shah, Kay Johnson and Deb Riechmann in Kabul contributed to this report.