"There have been long standing relationships between the Pakistani intelligence officials and these terrorist groups. So, we don't expect things to change overnight. We expect incremental changes over time," the official told PTI.
His comments came days after US President Donald Trump hit out at Pakistan for providing safe havens to "agents of chaos" that kill Americans in Afghanistan and warned Islamabad that it has "much to lose" by harbouring terrorists.
"We will be able to see when these changes start to happen. They (might) not become immediately apparent to the public, but we're confident that when Pakistan takes the steps we're asking it to do, we'll know it and we'll be able to assess. And so, our security aid will be conditioned on the steps that we expect them to take against, in particular, the Taliban-Haqqani Network," the official said.
The United States, the official said, is monitoring the situation carefully in Pakistan and expects some progress.
"It wouldn't be appropriate for me to give exact timelines that we're dealing in. But, certainly there is an expectation that we'll start to see some changes in the very near future," the official said when asked if the Trump administration has set a time line for progress in action being taken by Pakistan against the terrorist groups.
The official was responding to a series of question on the statements coming out of Pakistan, which are generally in strong opposition to the Trump’s South Asia strategy.
"How do you see Pakistan's reaction? Do you think that they would be, given these kind of reactions that's coming up in public domain, think they will be cooperating this time with you on counter-terrorism issues?" the official was asked.
"I think the President was very clear that we are going to take a different approach to that stand. There's a lot of frustration (in the US) with the continued safe havens in Pakistan. But we believe there is hope for greater cooperation from Pakistan on these issues. It's Pakistan's choice.
Pakistan has much to benefit from by cooperating with the US and cracking down on some of these groups," the official said. And Pakistan has much to lose if it fails to do so, the official warned.
"We're not going to talk about the precise steps that the US is considering with regard to its relationship with Pakistan. We'll reserve that for our private discussions on Pakistan. We'll just simply say that it's extremely important to this administration that Pakistan take tangible steps against the groups that continue to support attacks against US service members and US officials in Afghanistan," the official said, adding that the US will be working very closely with Pakistani officials to achieve that objective.
Pakistan's Foreign Minister Khawaja Asif is soon expected to visit the US and meet Secretary of State Rex Tillerson.
Ahead of the US visit, Asif is scheduled to travel to China, Russia and Turkey to hold meetings with their leaders on the Trump’s South Asia policy.
"We think that Pakistan will see that it's in its own interest to cooperate with the US. And that, when they're thinking about their core security interests in Afghanistan, they will assess that they can better achieve those objectives by being in a cooperative relationship with the US, rather than a contentious relationship. These are the kinds of conversations that we're having with Pakistan," the official added.