Fearing at the possibility of attacks against the US emanating from Pakistan, Secretary of State Hillary Clinton on her second visit to the country has called on Islamabad to take further and specific actions against militant networks, BBC reported.

Without going into details, BBC said that Clinton in an interview in American Embassy compound in Islamabad had indicated that US wanted Pakistan to do more to tackle the Haqqani network.

She also said that the US State Department was looking into the possibility of listing the Haqqani network as a terrorist organisation.

Describing the Haqqani network as "violent and feared", BBC said, the organisation operates along the Pak-Afghan border and is seen as a main threat to US and NATO troops in Afghanistan.

"We have designated a number of their leaders over the year as terrorists, and we're now looking at whether and how to describe the group and if it meets the legal criteria for naming it", she said.

Clinton is the second major American leader to have called for listing of Haqqani network as a terrorist organisation. The idea was first mooted by Senator Carl Levin, Chairman of the Senate Armed Services Committee. 

Recently the top US commander in Afghanistan Gen David Petraeus had also taken up the issue with aides of President Barack Obama.

BBC said, the move could upset the Pakistan military, who have so far failed to take real action against the Haqqani network, and are thought to be keeping a group as leverage to increase their influence inside Afghanistan ahead of an eventual US withdrawal.

On US fears of more attacks in America emanating from Pakistani soil, Clinton made it again clear that "There is no doubt in anyone's mind that should an attack against the US be traced back to Pakistan it would have devastating impact on our relationship."

The Secretary of State said progress had been made in addressing the trust deficit between the two countries.

"The Taliban are active in both Afghanistan and Pakistan. All in all we are making progress but I don't want to oversell it, because everyday I know how much more needs to be done", she said.

"But there is openness and a level of candour that is more helpful in dealing with our ongoing challenges", US Secretary of State said.

BBC said Clinton has come to Islamabad, on her second visit as Secretary of State, armed with USD 550 million for water, agriculture and energy projects to chip away some more at the deep-seated mistrust of America in Pakistan.