The remarks by Adm. Mike Mullen on the murder of journalist Syed Saleem Shahzad came at a time when relations between the uneasy allies were already seriously damaged after the killing of Osama Bin Laden in Pakistan by US forces. “It is extremely irresponsible and unfortunate statement,” Information Minister Firdous Ashiq Awan told a news conference.

“This statement will create problems and difficulties for the bilateral relations between Pakistan and America. It will definitely deal a blow to our common efforts with regard to the war on terror,” she said.

Shahzad, who worked for the Hong Kong-based Asia Times Online, disappeared from Islamabad on May 29. His body was found in a canal two days later, bearing what police said were signs of torture.

The killing prompted intense speculation about the involvement of Pakistan military’s powerful spy agency, Inter-Services Intelligence (ISI), but Mullen said on Thursday he could not confirm involvement of the ISI. In the most explicit remarks to date on the case by a senior US official, Mullen said he did not have a “string of evidence” linking Shahzad’s death to a specific government agency. But he added: “I have not seen anything that would disabuse that report that the government knew about this.

“It was sanctioned by the government, yeah,” he told reporters from the Pentagon Press Association.

Journalists have increasingly been targeted in Pakistan, and in December the Committee to Protect Journalists said it had become the most dangerous place in the world for journalists, with at least eight killed in 2010.

A Pakistani government spokesman earlier said the government had set up a judicial commission to investigate Shahzad’s death, and that all information should be shared with the commission.

“If any statement is issued other than this way, it will be considered an attempt to influence the proceeding of the Commission.” the spokesman said. “It seems that some elements are trying to use this issue against the elected democratic government and Pakistan.”

Shahzad had been investigating and writing about alleged links between the ISI and militant groups.

He had reported that an attack on a major navy base in the southern port of Karachi in May was carried out by Al-Qaeda militants after talks failed to secure the release of two naval officials accused of having ties to militants.

The attack on the PNS Mehran base was launched after the killing of Bin Laden by US Navy SEALs in a secret mission in the northwestern garrison town of Abbottabad on May 2. A small group of militants held out for 16 hours at the base against 100 commandos and rangers.