Washington Friday condemned the "brutality and cowardice" of the killing of an American blogger of Bangladeshi origin and called his murder an assault on the country's "proud tradition" of free speech.
"The United States condemns in the strongest terms the brutal murder of Avijit Roy," State Department spokeswoman Jen Psaki said.
"He was taken from us in a shocking act of violence," she told reporters.
Roy, founder of Mukto-Mona (Free-mind) blog, was attacked by unknown assailants as he returned home from a book fair with his wife on Thursday evening, and hacked to death with machetes.
He had allegedly received threats from Islamic militants due to his books and a prominent blog which championed liberal secular writing in the Muslim-majority nation.
No-one has yet claimed responsibility for the attack.