President Donald Trump’s decision to cancel Afghan peace talks will cost more American lives, the Taliban said on Sunday while the US promised to keep up military pressure on the militants, in a stunning reversal of efforts to forge a deal ending nearly 20 years of war in Afghanistan.

The Islamist group issued a statement after Trump unexpectedly cancelled secret talks planned for Sunday with the Taliban’s major leaders at the presidential compound in Camp David, Maryland. He broke off the talks on Saturday after the Taliban claimed responsibility for an attack in Kabul last week that killed an American soldier and 11 others.

Zabihullah Mujahid, a Taliban spokesman, criticised Trump for calling off the dialogue and said US forces have been pounding Afghanistan with attacks at the same time.

“This will lead to more losses to the US,” he said. “Its credibility will be affected, its anti-peace stance will be exposed to the world, losses to lives and assets will increase.”

In Washington, secretary of state Mike Pompeo said that Afghan peace talks were on hold and Washington would not reduce US military support for Afghan troops until it was convinced the Taliban could follow through on significant commitments.

The US has recalled special envoy for Afghanistan Zalmay Khalilzad to chart the path forward, Pompeo said in appearances on Sunday TV news shows. Asked on Fox News Sunday whether Afghan talks were dead, Pompeo said, “For the time being they are.”

Trump has long wanted to end US involvement in Afghanistan — since his days as a candidate — and American diplomats have been talking with Taliban representatives for months about a plan to withdraw thousands of US troops in exchange for security guarantees by the Taliban.

US and Taliban negotiators struck a draft peace deal last week that could have led to a pullout of troops from America’s longest war. There are currently 14,000 US forces as well as thousands of other Nato troops in the country, 18 years after its invasion by a US-led coalition following the September 11, 2001, al Qaida attacks on the US.

Fighting in Afghanistan has continued amid the talks and recent assaults by the Taliban cast doubts over the draft deal. As violence has escalated, Afghan leaders including President Ashraf Ghani have been increasingly critical of the deal and encouraged the Taliban to enter direct talks.

Asked whether the collapse of talks put a US troop pullout on hold as well, Pompeo said the issue would be discussed. “The President hasn’t yet made a decision on that,” he said on ABC’s This Week.

Trump decided to get personally involved to get the agreement to the finish line at Camp David after “real progress” had been made in talks, Pompeo said.

“President Trump ultimately made the decision,” Pompeo told Fox. “He said, ‘I want to talk to (President) Ashraf Ghani. I want to talk to these Taliban negotiators. I want to look them in the eye. I want to see if we can get to the final outcome we needed.’”

The US President has touted his skills as a negotiator and personal rapport with world leaders.

Trump was criticised, even by some fellow Republicans, for having offered to host on US soil a militant group that has killed American troops and had sheltered al Qaida leader Osama bin Laden after the September 11, 2001 attacks.

“Camp David is where America’s leaders met to plan our response after al Qaida, supported by the Taliban, killed 3000 Americans on 9/11,” US Representative Liz Cheney, a Republican whose father, Dick Cheney, was US vice-president at the time of the attacks, wrote on Twitter on Sunday.