Washington, Sept 15: US Defense Secretary Leon Panetta has warned that his country will not allow attacks on US forces by Pakistan-based militants, such as the Haqqani network, to go on.

Referring to this week's 20-hour militant assault against the US Embassy and NATO headquarters in Kabul, Panetta said it is unacceptable that the Haqqanis are able to launch such deadly attacks in Afghanistan and then flee to sanctuaries across the border in Pakistan.

"The message they need to know is: we''re going to do everything we can to defend our forces," a foreign news agency quoted Panetta, as telling reporters travelling with him to San Francisco for meetings with Australian officials.

He expressed frustration with Islamabad for making `very little progress' in acting against the Haqqani network, but refused to say whether the US plans to take any new military actions to curb such attacks in future.

"Time and again we''ve urged the Pakistanis to exercise their influence over these kinds of attacks from the Haqqanis, and we have made very little progress in that area," Panetta said. "I''m not going to talk about how we''re going to respond. ... We''re not going to allow these types of attacks to go on," Panetta said.

Panetta''s remarks reflect growing US impatience over Islamabad''s reluctance to go after the Haqqanis, who are connected to both the Taliban and Al Qaeda and present the most significant threat to Afghanistan''s stability, Fox News reports.

American officials have repeatedly pressed the Pakistanis to move against terrorist havens in the border region, which is reportedly used by the Haqqanis to launch attacks against US and Afghan forces across the border. (ANI)