With a tougher regional policy announced by the United States (US) on Tuesday, National Security Council (NSC) Spokesperson Michael Anton warned Pakistan that it is "on notice from this president, from this administration", Politico reported.

Anton, speaking to reporters on a conference call, was quoted by Politico as saying that "business as usual [with Pakistan] as it has been up to now is over", and that the US could impose sanctions on terrorist groups, including the Haqqani network, and any Pakistani officials "who are tied to these kinds of groups, you know, in ways that they shouldn't be".

"I think the important takeaway for the Pakistani government last night is that, you know, they should understand that they’re on notice from this president, from this administration," he told Politico, referring to what appeared to be a shift in the US policy regarding Pakistan.

"The United States has been really patient with Pakistan for a really long time. We haven’t been getting a good deal from them," he claimed.

Earlier today, US President Donald Trump had cleared the way for the deployment of more US troops to Afghanistan, backtracking from his promise to swiftly end America's longest war.

"We can no longer be silent about Pakistan's safe havens for terrorist organisations," Trump had said, warning that vital aid to Pakistan could be cut.

"We have been paying Pakistan billions and billions of dollars at the same time they are housing the very terrorists that we are fighting," the US president claimed. "That will have to change and that will change immediately."

Anton, taking note of US security aid to Pakistan, claimed America receives in return, at best, "indifference to border crossing and terrorist safe havens and sanctuaries" in the tribal regions along the Pak-Afghan border, Politico reported.

"In the worst case," he alleged, Pakistan is guilty of "active direct support" for terrorist groups.

'Pakistan's concerns over India-Afghan ties an excuse'

Anton dismissed Islamabad's concerns over growing India-Afghanistan ties, terming them an "excuse", according to Politico.

"What India is doing in Afghanistan is not a threat to Pakistan," he claimed. "They’re not building military bases. They’re not deploying troops. They’re not doing the things that would constitute encirclement, for lack of a better term, which is one of the things that the Pakistanis complain about," he alleged.

Explore: RAW operating from Afghanistan to create unrest in Pakistan: Gen Zubair Hayat

The NSC spokesperson claimed that Trump had benefited from an outsider's perspective on the Pak-US relationship, Politico reported, by foregoing 'conventional wisdom' that "however much the Pakistanis double-deal you and lie to you and don’t cooperate, you have no choice but to just keep the status quo."

"How do we get the Pakistan to behave better? The answer is we have leverage points over Pakistan that the strategy contemplates we will use. Ultimately whether they behave better or not is completely up to them," Anton said.

"They may calculate that it’s more important to, you know, remain allied with terrorists, it’s more important to give terrorists safe haven, it’s more important to do all the nasty things that they’ve been doing that we don’t like than it is to have a good relationship with the United States," he alleged.

"If so, that’s a choice that they will make and then we will make choices based on their choice," he warned.

The US been mulling a harder approach towards Pakistan for some time now. In June, the Trump administration reportedly discussed expansion of drone strikes, redirecting or withholding some aid to Pakistan, and perhaps eventually downgrading its status as a major non-Nato ally.

Bills suggesting curbs on US assistance to Pakistan were also okayed by the US House of Representatives last month.

Pakistan has repeatedly denied allegations that it has supported Haqqani militants, and has announced stronger counter-terrorism measures in the form of military operations and stepping up border management along the shared border with Afghanistan and Iran.

Director General (DG) Inter-Services Public Relations (ISPR) Maj Gen Asif Ghafoor this week announced the successful completion of Operation Khyber-4 which sought to target terrorists in Rajgal Valley, which he said was "the most critical area in the Federally Administered Tribal Areas (Fata)".

Read more: Army launches Operation Khyber-4 in Rajgal Valley

The DG ISPR had said that army leadership held a "very candid discussion" with visiting US delegations, including US Central Command chief Gen Joseph Votel.

"We made clear how Pakistan has acted indiscriminately against all terrorists. There are no terrorist hideouts in Pakistan... We have operated against all terrorists, including the Haqqani network, and they [the delegations] were given certain evidence. But there is global politics, there is regional politics, India is playing a role," Maj Gen Asif Ghafoor had said.

Gen Votel, after his visit, said he came away with "increased understanding of the counterterrorism and counter-insurgency efforts of the Pakistani government".

Explore: US Centcom chief stresses sustained ties with Pakistan

Gen Votel has, in the past, informed US lawmakers that Pakistan has "done some things that have been helpful to us... against the principal concerns we have; the Haqqani network and Taliban". He has also stressed the need for focus and persistence in this area, and continuing to engage with Pakistan on the matter.

Read more: Pakistan did ‘helpful things’ against Haqqanis: US general

Ambassador Aizaz Chaudhry has rejected claims that the Haqqani network operates in Pakistan. The Haqqani network "is on the run, as far as we are concerned", Chaudhry said earlier this year. "They have moved into Afghanistan and need to be taken care of there."

Top military leadership have also shared concerns that hostile intelligence agencies, including India's Research and Analysis Wing, are operating from Afghanistan and other locations to foment unrest in Pakistan, particularly Balochistan.

Chairman Joint Chiefs of Staff Committee Gen Zubair Mahmood Hayat has said their "designs [and] oblique actions to sabotage CPEC are also well known", adding that Pakistan's security forces along with law-enforcement agencies are playing a crucial role in tackling "external state-sponsored elements operating through local proxies".

Read more: RAW runs special cell to sabotage CPEC, says secretary defence