ISLAMABAD: The United States' decision to designate the Haqqani network as a terrorist organization shows it is not sincere about peace efforts in Afghanistan, senior commanders of the group said on Friday.

The move will also bring hardship for US Sergeant Bowe Bergdahl, who is being held by the militants, the commanders told Reuters by telephone from an undisclosed location.

The United States is designating the Pakistan-based Haqqani network, accused of high-profile attacks in Afghanistan, as a terrorist organization, Secretary of State Hillary Clinton said on Friday, in a move that would trigger sanctions against the group and turn up the heat on Pakistan's government.

US officials have long accused Pakistan of supporting the network, an allegation Islamabad denies.

The Haqqanis, who are allied with the Afghan Taliban, are some of the most experienced fighters in Afghanistan and have carried out several high-profile attacks on Western targets.

Senior commanders from the network said the decision to designate the group as terrorists could endanger efforts to reach a peaceful settlement to the Afghan conflict before most Nato combat troops withdraw by the end of 2014.

“It means the United States is not sincere in their talks. They are on the one hand claiming to look for a political solution to the Afghan issue while on the other they are declaring us terrorists,” said one of the commanders.

“So how can peace talks succeed in bringing peace to Afghanistan?”

Whether or not to brand the group a terrorist organization has been the subject of intense debate within the administration of US President Barack Obama, with some officials arguing it would have little real impact, but would risk setting back Afghan reconciliation efforts.

The New York Times earlier reported that senior US officials who argued against blacklisting the group were concerned it could jeopardise the fate of Bergdahl, who disappeared from his base in southern Afghanistan in June 2009 and is believed to be being held by the militants.

“Until now we treated him very well but this move by the United States will of course create hardships for him,” another Haqqani commander told Reuters.