Islamabad's failure to stop terrorist attacks on India or take action against Lakshar-e-Taiba leader Hafeez Saeed were not factors behind the US suspending most military assistance to Pakistan, State Department Spokesperson Heather Nauert has said.

"To my knowledge, that (aid freeze) has nothing to do with that," she said on Thursday when asked at a news briefing here if the US was also motivated to take the action by the cross-border terrorism against India and the 2008 terror strike on Mumbai masterminded by Saeed.

"We have certainly expressed our concern about the mastermind of the 2008 Mumbai attacks being let out of house arrest in Pakistan.

"We've been very clear about our displeasure with that individual being let go, and that's why we like to remind people that there is a $10 million 'Rewards for Justice' program out for him," she said.

The US was concerned about the risks to its own personnel in Afghanistan from groups targeting them.

Nauert named the Afghan Taliban and the Haqqani Network among terrorist organisations against whom Pakistan has to take "decisive action" for lifting the freeze of the delivery of military equipment and transfer security-related funds.

Those groups "continue to find sanctuary inside Pakistan as they plot to destabilise Afghanistan and also attack the US and allied personnel", she said.

The freeze announced on Thursday was in addition to the $255 million in foreign military assistance that the Trump administration said in August it was withholding, she said.

She noted that Pakistan selectively acted against some terror organisations.

"The security services have been effective in combating the groups that target Pakistani interests such as Al Qaeda, IS (Islamic State) and the Pakistani Taliban," she added.