"I can confirm that US forces did capture... Terrorist leader Latif Mehsud," State Department deputy spokeswoman Marie Harf said, describing him as a senior commander in the Tehreek-e-Taliban Pakistan (TTP).
She gave no details of the operation and did not say where or when his capture took place.
But the Washington Post reported that he had been seized recently in eastern Afghanistan, and was snatched away from Afghan intelligence operatives who had been trying to recruit him as a possible go-between for peace talks between Kabul, Islamabad and the Taliban.
President Hamid Karzai, with whom Kerry met today, was reportedly livid about Mehsud's capture.
"The Americans forcibly removed him and took him to Bagram," a Karzai spokesman, Aimal Faizi, told the Post.
Mehsud had only agreed to meet with operatives of Afghanistan's National Directorate of Security after months of conversations, he said.
Afghan authorities believed their contacts with Mehsud has been one of the most significant operations carried out by Afghan forces, who are gradually assuming sole control for the country's security, Faizi told the Post.
"Mehsud is a senior commander in TTP and served as a trusted confidante of the group's leader Hakimullah Mehsud," Harf said.
She told reporters that the TTP had claimed responsibility for the attempted bombing of Times Square, New York, in 2010.
The group "had also vowed to attack the US homeland again," Harf said, adding it had also been behind attacks on US diplomats in Pakistan as well as incidents that killed Pakistani civilians.
Karzai in August asked Pakistan to help arrange peace talks between his government and Taliban insurgents, during a visit to Islamabad for his first talks with newly elected Prime Minister Nawaz Sharif.
