A day after Washington confirmed suspending $255 million of military aid to Pakistan, US Press Secretary Sarah Sanders said that the actions being taken against Islamabad are a follow-up to Donald Trump's South Asia policy announced last year.

"The president outlined a new strategy for Afghanistan and South Asia past year in August. At that time, he laid out [a policy] and said that Pakistan is not fulfilling its obligations," said Sanders during the White House press briefing on Tuesday.

"The President is simply following through on a commitment that he made [...] we know that Pakistan can do more to fight terrorism, and we want them to step up and do that."

Also read: Pakistan's measured response to Trump's tweet is a step in the right direction

“We can no longer be silent about Pakistan's safe havens for terrorist organisations,” Trump had said in August last year, warning at the time that vital aid could be cut.

The press secretary was pressed about the timing of Trump's tweet about Pakistan more than once during the briefing. When asked if there was any particular incident that prompted Monday's tweet, Sanders said: "This is something that the president has been following and has talked about back during August, when he laid out his Afghanistan and South Asia strategy. And this is something that the administration continues to watch on a daily basis — and I can’t go into any further detail beyond that."

Sanders told the press that further action against Pakistan — and other countries that did not vote with the United States on Jerusalem at the United Nations — would be announced in the next 24-48 hours.

Worsening relations

The White House's move to suspend military aid on Tuesday has been seen as the first step to implementing President Donald Trump’s pledge to tighten economic restrictions on Pakistan.

Military aid to Islamabad was cut after Trump, in a tweet, accused Pakistan of of being a liar.

The tweet had come in the aftermath of an increasingly terse back-and-forth between Washington and Islamabad since Trump announced his administration's latest national security strategy.

Explore: 'Pakistan needs to improve its narrative': Politicians, analysts weigh in on Trump statement

During the announcement, the US president had been quick to remind Pakistan of its 'obligation' to help America "because it receives massive payments" from Washington every year.

"We have made clear to Pakistan that while we desire continued partnership, we must see decisive action against terrorist groups operating on their territory. And we make massive payments every year to Pakistan. They have to help," the US president had said.

A Pentagon report to the US Congress, released to the media on Dec 17, had said Washington would also take 'unilateral steps' in areas of divergence with Pakistan while expanding cooperation between the two countries where their interests converge.

Subsequently, US Vice President Mike Pence had, in a surprise visit to Afghanistan's Bagram airbase on Dec 22, warned that Trump has "put Pakistan on notice" in what was the harshest US warning to Islamabad since the beginning of the Afghan war over 16 years ago.

The Pakistan Army spokesman, Maj Gen Asif Ghafoor, had at a press conference last week asserted that the aid Pakistan received from the US was "reimbursement for support we gave to the coalition for its fight against Al Qaeda."

"Had we not supported the US and Afghanistan, they would never have been able to defeat Al Qaeda," he had said.

"The armed forces are working with friends and want to continue doing so, but there can be no compromise on our national honour. We do not want a conflict with our friends, but will ensure the security of Pakistan," he had added.

His briefing was considered perhaps the strongest-ever reaction from Islamabad since US functionaries began alluding to the possibility of unilateral action.

Hitting back at the US, the civilian-controlled Foreign Office (FO) had also warned against the "malicious campaign" being "used to trivialise Pakistan's achievements in the war against terrorism", and noted that "allies do not put each other on notice."

The FO had further complained that recent US statements are "at variance with the extensive conversations we [Islamabad] have had with the US administration".