"The clear message that is being conveyed over the last week that we hope the Government of Pakistan would take steps against the militants located on the Pakistani side of the border, who carry out attacks against American and Afghan forces inside Afghanistan," Pentagon spokesman George Little told reporters.
"The Secretary of Defence (Leon Panetta) was clear on Thursday in testimony (before a Congressional committee) that in terms of options that might be looked at to pursue militants, we are not going to discuss what options may or may not be," Little said.
Branding Haqqani networks' safe havens in Pakistan as "extremely troubling" and a matter of great concern, another top US official said Washington wants to see action taken against them, as the terror outfit's alleged links with Pakistan's ISI continued to cloud ties between the once close allies.
"US has a clear position on this", State Department spokesperson Mark Toner said, acknowledging that he had seen media reports from Pakistan that they will not take any action against the Haqqanis at this point of time.
"We believe that these kind of safe havens are extremely troubling and indeed a matter of great concern and dangerous development for both the US and for Pakistan. So we want to see action taken against them," Toner said in indications that Washington was steadfast on its stand against the outfit.
The top US official said the Obama administration is moving to blacklist the group by placing it on its list of banned terror groups. Brushing aside reports that Washington was dragging its feet on action against the terror outfit, Toner said seven top leaders of the Haqqani network, founded by Jalaluddin Haqqani and run by his son Sirajuddin, have been placed under US sanctions since 2008.
"Certainly FTO (foreign terrorist organisation) designation is something under review," he told reporters. "But the idea that we haven't gone after the Haqqani network at all, I think is a mischaracterisation."
Toner said among those who had been slapped with sanctions included the network's kingpins like Sirajuddin and his brother Badruddin Haqqani and close family associate Sangeen Zadran, all of whom had been designated as terrorists by the State Department.
Four other Haqqani clansmen Nasiruddin Haqqani, Khalil Haqqani, Ahmed Jan Wazir and Fazl Rabi had been targeted by the Treasury Department. Echoing Toner's comments, Pentagon spokesman Little insisted Islamabad had been given a "clear message" to act against the extremist groups such as Haqqani network that operate from its soil.
"The lines of communication remain open with Pakistan", Little said, adding the relationship is complicated but an essential one. The alliance between Pakistan and the US in the 10-year war in Afghanistan and against al-Qaeda hit rock bottom after top US military officer, Chairman of the Joint Chiefs of Staff Admiral Mike Mullen, directly accused Pakistan's intelligence services on Thursday of supporting Haqqani network's attack on the American embassy in Kabul, a truck bombing on a NATO outpost and a June attack on Kabul's InterContinental hotel.
The Pentagon spokesman acknowledged "very clear challenges" in the US relationship with Pakistan and said "as far as our concerns about the Haqqani network, that's been raised at the highest levels."
Secretary of State Hillary Clinton has spoken about it, apart from Secretary of Defence Panetta and others like Mullen.
"And it's certainly a matter of concern, but we're addressing these concerns by working constructively with the Pakistani Government," Little said.
But Toner insisted that President Barack Obama's administration was committed to "working constructively" with Islamabad.
The comments from the top American official come as Pakistan Prime Minister Yousuf Raza Gilani called a rare cross-party conference on Thursday, although he dismissed the US charges as little more than finding a scapegoat for Washington's "disarray" in Afghanistan.
Pakistan army chief Gen Ashfaq Parvez Kayani scrapped a visit to London as Islamabad refused to bow to mounting US demands for action against the al-Qaeda-linked Haqqani extremists.