The US military's top officer said on Thursday Pakistan's government may have sanctioned the killing of a Pakistani journalist, voicing grave concern over the attack.
Asked about media reports that Islamabad sanctioned or approved the killing of the reporter, Admiral Mike Mullen said: "I haven't seen anything that would disabuse that report."
He said he was "concerned" about the incident and suggested other reporters had suffered a similar fate in the past. "His (death) isn't the first. For whatever reason, it has been used as a method historically."
While acknowledging that Pakistani officials have denied the government had any role in the death of Saleem Shahzad, Mullen said the episode raised worrying questions about the country's current course.
"It's not a way to move ahead. It's a way to continue to quite frankly spiral in the wrong direction," said Mullen, who has held numerous meetings with Pakistani counterparts during his tenure as chairman of the US Joint Chiefs of Staff.
The New York Times, citing US officials, reported Monday that the powerful Inter-Services Intelligence (ISI) agency ordered the killing of the 40-year-old Shahzad to muzzle criticism.
Mullen said he could not confirm whether the ISI was behind the killing.
The ISI has denied as "baseless" allegations that it was involved in the murder of Shahzad, who worked for an Italian news agency and a Hong Kong-registered news site.