Pakistan has been accused of playing a "double game" and harbouring "terrorists" by Nikki Haley, the US ambassador to the UN, as the war of words continues between the two countries over military aid.

Haley's comments come a day after President Donald Trump threatened to cut aid to Pakistan for allegedly lying to the US and offering "little help" in hunting "terrorists" in neighbouring Afghanistan.

"There are clear reasons for this. Pakistan has played a double game for years," Haley told reporters at the UN headquarters in New York.

"They work with us at times, and they also harbour the terrorists that attack our troops in Afghanistan," Haley told reporters at the UN headquarters in New York. That game is not acceptable to this administration."

Urging greater cooperation from Pakistan in the fight against "terrorism", she said Trump "is willing to go to great lengths to stop all funding for Pakistan".

On January 1, in his first tweet of the new year, Trump said: "the United States has foolishly given Pakistan more than 33 billion dollars in aid over the last 15 years, and they have given us nothing but lies and deceit, thinking of our leaders as fools".

The United States has foolishly given Pakistan more than 33 billion dollars in aid over the last 15 years, and they have given us nothing but lies & deceit, thinking of our leaders as fools. They give safe haven to the terrorists we hunt in Afghanistan, with little help. No more! — Donald J. Trump (@realDonaldTrump) January 1, 2018

Trump's tweet appeared to have further increased tensions between countries and sparked a strong reaction from Islamabad.

On Monday, Pakistan's Foreign Minister Khawaja Asif told the Pakistani TV network Geo: "We have already told the US that we will not do more, so Trump's 'no more' does not hold any importance."

Pakistani Prime Minister Shahid Khaqan Abbasi called a meeting of the National Security Committee (NSC) on Tuesday who expressed "deep disappointment" over Trump's comments.

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Pakistan's ambassador to the UN, Maleeha Lodhi, rejected the allegations and said her country's cooperation was not based on aid but national interests.

"We have contributed and sacrificed the most in fighting international terrorism and carried out the largest counter-terrorism operation anywhere in the world," she said in an email sent to Al Jazeera on Wednesday.

"US spokespersons should not shift the blame for their own mistakes and failures onto others."

White House Press Secretary Sarah Sanders added that the US would lay out specific actions against Pakistan in the next 24 to 48 hours.

Relations between the US and Pakistan have deteriorated since the Trump administration began taking a hard line on Afghanistan last year.

On Thursday, Pakistan's military warned the US against the possibility of taking unilateral action against armed groups on its soil.

Michael Kugelman, a US-based analyst and Asia Program Deputy Director at the Woodrow Wilson Centre in Washington, DC, said Pakistan-US relations are in for "a very rough ride".

"Both sides have effectively dug in their heels, with the US demanding Pakistan to do more against terror and Pakistan insisting it has already done so much and won't do any more," he told Al Jazeera.

"This puts the relationship on a collision course.

"I don't expect a full rupture in ties, as each side benefits from some semblance of a workable relationship, but there will be dark days ahead."

Zafar Jaspal, an analyst on Pakistan and Professor of International Relations at Quaid-i-Azam University in Islamabad, said besides the "war on terror" in Afghanistan, there are "bigger games" at play in the context of Pakistan-US relations.

"There is a realignment in international politics and Pakistan is drifting towards Eurasian alliances, like China and Russia and that is not acceptable to the Americans."