KABUL, Afghanistan -- The number of Afghan police officers mistakenly killed by a U.S. airstrike in Afghanistan's embattled Helmand province has risen to 16, officials said Saturday.
Friday's strike on a security forces compound in the Gereshk district was part of a U.S.-supported operation against Taliban militants in the area.
"Afghan security forces had coordinated an airstrike with the foreign forces, but some Afghan National Police officers arrived at the area before the strike," said Omar Zwaak, spokesman for the governor of Helmand, suggesting a communications failure.
"Sixteen ANP officers were killed and another two were wounded," Zwaak said Saturday, adding that an investigation was still ongoing.
The incident came less than a week after Afghan officials praised U.S. air support for boosting morale among local forces battling to reclaim territory from the Taliban in Helmand.
On Monday, the U.S. support was instrumental in helping the Afghans retake the key district of Nawa, just south of the provincial capital Lashkar Gah, which the Taliban had held for nine months.
The U.S. military confirmed an airstrike it conducted Friday resulted in the deaths of friendly forces.
"We would like to express our deepest condolences to the families affected by this unfortunate incident," it said in a statement.
Helmand is valued by the Taliban for its extensive opium fields, the insurgent group's primary income source. The province has been the site of some of the fiercest fighting of the 16-year war, and hundreds of American troops have died there.
Meanwhile, another 11 Afghan police officers were killed on Friday during clashes with the Taliban in northern Badakhshan province.
Local officials said 20 more officers are missing and that it wasn't clear if they had been kidnapped or if they had escaped.
And in a third incident on Friday, five Afghan soldiers and one police officer were killed during fighting with the Taliban in western Farah province.
"Some 300 enemies tried to capture the center of Push-e-Koh district, but they faced strong resistance by the security forces," Mohammad Naser Mehri, spokesman for the governor of Farah said, adding that 12 Taliban fighters were also killed.
He confirmed that the government remained in control of the district.
The assaults by a resurgent Taliban come as the group is said to control more territory now than at any time since 2001, when a U.S.-led invasion ousted them from power.
On Friday, U.S. Defense Secretary Jim Mattis told reporters at the Pentagon that a new strategy to break the stalemate with the militants would be announced "soon." It's expected to include the deployment of up to 5,000 additional U.S. troops and more authority to target the Taliban offensively.
Mattis said he had already installed some adjustments to the fight in Afghanistan, where the United States has drastically increased its use of airstrikes in 2017. As of June 30, U.S. and NATO aircraft had dropped more than 1,600 munitions in Afghanistan this year, according to Air Forces Central Command data. In 2016, it dropped only 545 throughout the entire year.
Stars and Stripes reporter Corey Dickstein contributed to this article.