US Secretary of State Hillary Clinton has condemned the murder of a Pakistani journalist who had recently written an article about al-Qaeda infiltration in Pakistan's navy.
Saleem Shahzad's body was found on Tuesday two days after he went missing.
Earlier a Human Rights Watch researcher said he had "credible information" that Shahzad was in the custody of Pakistani intelligence.
Mr Shahzad's funeral is taking place on Wednesday in the city of Karachi.
Pakistan has ordered an immediate inquiry into his kidnapping and murder.
"The United States strongly condemns the abduction and killing of reporter Syed Saleem Shahzad," Ms Clinton said in a statement.
"His work reporting on terrorism and intelligence issues in Pakistan brought to light the troubles extremism poses to Pakistan's stability," she said.
Mrs Clinton also welcomed the investigation into the killing.
Mr Shahzad's funeral will take place in his native city of Karachi on Wednesday. His article about al-Qaeda infiltration in Pakistan's navy was recently published.
The post mortem report said that there were "15 torture marks" on his body, and no bullet wounds.
It said the death was probably caused by a fatal blow to the body in the chest region.
Mr Shahzad had reported recently that the militant group had launched the deadly assault on the Mehran base in Karachi, the headquarters of the navy's air wing, on 22 May because talks had failed over the release of several naval personnel arrested on suspicion of links to al-Qaeda affiliates.
At least 14 people were killed and two navy warplanes destroyed.
On Monday, a former navy commando and his brother were detained for their alleged role in helping plan the raid, which embarrassed the military.
The 40-year-old's body was found in a canal in Mandi Baha Uddin in Pakistan's northern Gujarat district.
Earlier, Human Rights Watch researcher Ali Dayan Hasan said Mr Shahzad had recently complained about being threatened by the intelligence arm of the Pakistan military, the Inter Services Intelligence Directorate (ISI).
A senior Pakistani intelligence official told the Associated Press it was "absurd" to say that the ISI had anything to do with Mr Shahzad's death.
The dead man, who had a wife and three children, worked for the Italian news agency Adnkronos International (AKI) and was Pakistan bureau chief for Asia Times Online.
Human rights groups recently called Pakistan the most dangerous place in the world for journalists to operate, saying they were under threat from Islamist militants but also Pakistan's military and intelligence agencies.
