Washington, May 12 (IANS): Top Democrats and Republicans on the House and Senate Intelligence panels have demanded that the Obama administration "immediately" label the Pakistani-based Haqqani Network a terrorist organization.

The group has claimed responsibility for many attacks on NATO forces and the US embassy in Kabul, but the administration has been reluctant to label them terrorists as it pursues negotiations with insurgents in Afghanistan.

In a letter to Secretary of State Hillary Clinton on return from a trip to Afghanistan last week, the lawmakers said their concerns about the group were "reaffirmed" after meeting with President Hamid Karzai and US officials.

"It was clear that the Haqqani Network continues to launch sensational and indiscriminate attacks against US interests in [Ryan] Crocker told us last week that there have been no such talks since late last year, and that President Afghanistan and the group poses a continuing threat to innocent men, women, and children in the region," they wrote.

"We understand there may have been reluctance within the Administration to designate the Haqqani Network while Special Representative for Afghanistan and Pakistan Marc Grossman attempted to negotiate a reconciliation agreement with the Taliban - a deal that may have included or affected the Haqqani Network," the letter said.

"However, Ambassador Karzai has opposed their continuation," it added.

The letter was signed by Senate Intelligence Committee's Democratic Chairperson Dianne Feinstein and top Republican member Saxby Chambliss and by House Intelligence Committee's Republican Chairman Mike Rogers and ranking Democratic member Dutch Ruppersberger.

State Department spokesperson Victoria Nuland told reporters Friday that the administration was reviewing the letter from the Congress.

"We continue to talk to the Congress about these issues and we continue our internal review of the larger question of the network as a whole," she said.

Many of the key leaders of the Haqqani Network, including Sirajuddin Haqqani, Badruddin Haqqani, Sangeen Zadran, Mali Khan and five others have been individually designated, Nuland said.

The US has "been talking to the Pakistani Government about the Haqqani Network for arguably years," she said. This was a key subject when Clinton went there last October and "we're continuing to work on it together."