The United States announced on Thursday it was suspending security assistance to Pakistan for failing to take “decisive action” against the Afghan Taliban and the Haqqani network, which Washington believes is destabilizing the region.

The state department’s declaration signaled growing frustration over Pakistan’s cooperation in fighting terrorist networks, but it was not immediately clear how much money and materiel was being withheld.

The vague details suggested the primary goal was to substantiate Donald Trump’s surprising New Year’s Day tweet that accused Pakistan of playing US leaders for “fools”.

A state department spokeswoman, Heather Nauert, said she could not provide a dollar value for the suspended aid, but said it was in addition to the $255m in military aid the US put on hold in August.

“Today we can confirm that we are suspending … security assistance only to Pakistan at this time until the Pakistani government takes decisive action against groups including the Afghan Taliban and the Haqqani network. We consider them to be destabilizing the region and also targeting US personnel,” she told a regular news briefing.

Nauert said details were still being worked out on the additional funds, and referred questions to the defense department. Earlier on Thursday, the defense secretary, Jim Mattis, said the policy on military aid was “still being formulated”.

The new action targets payments of so-called Coalition Support Funds that the US pays to Pakistan to reimburse it for its counter-terrorism operations. Those funds are typically paid later in the year, and already require US certification, so the effect of Thursday’s announcement was unclear.

On Monday, Trump said the US had “foolishly” given Pakistan more than $33bn in aid in the last 15 years and had gotten nothing in return but “lies and deceit”. He reiterated longstanding allegations that Pakistan gives “safe haven to the terrorists we hunt in Afghanistan”.

Trump unveiled in August a south Asia strategy aimed at ending the stalemate in the US war in Afghanistan, now entering its 17th year. Nauert said that despite sustained high-level engagement with Pakistan’s government, “the Taliban and Haqqani network continue to find sanctuary inside Pakistan as they plot to destabilize Afghanistan and attack US and allied personnel”.

She told reporters that until Pakistan takes “decisive action” against those groups, security assistance was suspended.

Civilian development and economic assistance to Pakistan is not affected.

Also on Thursday, the state department accused Pakistan of severe violations of religious freedom. It announced that it was placing Pakistan on a special watch list, pursuant to 2016 legislation. The step does not carry any serious consequences.

Pakistan’s embassy in Washington and mission at the United Nations did not immediately respond to a request for comment on Thursday.