Collette and Lindsay were killed in Kunduz province "as a result of wounds sustained while engaged in combat operations", officials said in a statement March 23.
The wounded troops were evacuated and are receiving medical care, officials said in the release.
Earlier, the Taliban claimed to have conducted an attack with a auto bomb, saying "multiple invaders" had been killed. The Defense Department said it was withholding the names of the fallen Americans until 24 hours after their families had been notified, per normal Pentagon policy.
There are 14,000 US troops in Afghanistan, many of whom train, advise and assist Afghan forces in their fight against the Taliban.
The US envoy to the peace talks, Ambassador Zalmay Khalilzad, left Afghanistan on Sunday following meetings with Afghan president Ashraf Ghani. He said Afghans want peace, but "they don't want to live the way that the Taliban want them to live".
The three deaths bring the number of US servicemembers killed in Afghanistan this year to seven. The insurgents dismiss the Afghan government as a USA puppet.
The fatalities, which bring to seven the number of US soldiers killed so far this year in Afghanistan, underscore the difficulties in bringing peace to the war-wrecked country even as Washington has stepped up efforts to find a way to end the 17-year war, America's longest.
For months, the US and the Taliban have been negotiating a potential agreement to end the 18-year war after President Donald Trump signaled that he was open to additional diplomatic conversations. The Taliban has balked at negotiating with the Afghans, which the group views as an American puppet organization.
You Can Never Go Wrong With Food
We do not know how it does it, but this food manages to hug us tightly as we eat all the stress away. Not the carbohydrates, but different categories for different days and different occasions.