U.S. Secretary of State Mike Pompeo said Sunday the Taliban "overreached" with a car bomb attack in a diplomatic area near the U.S. Embassy in Kabul, killing an American soldier — and that led U.S. President Donald Trump to pull back from planned Afghanistan peace talks at Camp David.

Pompeo said it was now up to the Taliban to "change their behaviour." America's top diplomat isn't saying whether or when peace talks would resume.

He said he hopes the insurgents "will recommit to the things that we've been talking to them about for months."

In the end, Pompeo said, "this will be resolved through a series of conversations. I hope the Taliban will agree to meet with the Afghan government."

Trump tweeted on Saturday night that he had cancelled a secret meeting, planned for Sunday at the presidential retreat in Maryland, with Taliban and Afghan leaders, and called off talks with the insurgent group. He cited the Thursday attack.

....an attack in Kabul that killed one of our great great soldiers, and 11 other people. I immediately cancelled the meeting and called off peace negotiations. What kind of people would kill so many in order to seemingly strengthen their bargaining position? They didn’t, they.... —@realDonaldTrump

Pompeo, who was booked on five Sunday news shows, said the United States and the Taliban were close to a deal.

"And then the Taliban failed to live up to a series of commitments that they had made, and when that happened President Trump said, 'I'm not going to take that deal. I'm not going to work with someone that can't deliver on their commitments."'

Not rewarding 'that behaviour'

He said Trump "broke it off," because he did not want to "reward that behaviour," referring to Thursday's attack.

Pompeo acknowledged that the attack was not the first during the period in which peace talks have been held. He also said the U.S. has been attacking the Taliban throughout this period.

U.S. President Donald Trump says he called off a planned secret meeting with the Taliban, and a separate one with Afghanistan's president, after a Taliban bombing that killed an American soldier and 11 other people. (Alex Brandon/Associated Press)

Pompeo said more than 1,000 Taliban have been killed in battle over the past 10 days alone.

The Taliban on Sunday said that Trump's abrupt decision to cancel the meet with the group's leaders on a "finalized" deal to end America's longest war would "damage the credibility" of the U.S., but they believe the U.S. will return to negotiations.

"Both sides were preparing for the announcement and signing of the agreement," the insurgent group said in a statement, saying they had been invited in late August but wanted to wait until the deal's signing. Now, "we will continue the ongoing jihad [against foreign occupation] and we firmly believe in the ultimate victory."

Trump's move puzzled observers, who pointed out that both the Taliban and U.S. and Afghan forces have increased fighting in recent months to strengthen their position in the talks. Civilians have suffered more than anyone in what was the world's deadliest war in 2018.

Trump's announcement Saturday evening was surprising because it would mean that the president was ready to host members of the Taliban just days before the anniversary of the Sept. 11, 2001, attacks. More than 2,400 U.S. troops have been killed since the U.S. invaded Afghanistan to go after the Taliban, which were harbouring al-Qaeda leaders responsible for 9-11.

In this file photo, Sen. Chuck Schumer, left, listens to Sen. Bob Menendez, right, speak on Capitol Hill. On Sunday, both men critiqued President Trump for how he has managed the U.S.-Taliban peace talks. (Yuri Gripas/Reuters)

Democrats said Trump's decision to nix the deal was evidence that he was moving too quickly to get one.

New Jersey Sen. Bob Menendez, the ranking Democrat on the foreign relations committee, said the talks were ill-conceived from the start because they haven't yet involved the Afghan government.

Sen. Chuck Schumer of New York also lashed out at Trump on Sunday, saying he "messed up" in calling for peace talks with the Taliban.

"For the U.S. to meet with the Taliban and not have the leader of Afghanistan to meet with the Taliban is something that's doomed to failure," Schumer said.

The Taliban have refused to negotiate with the government, which it sees as illegitimate and a puppet of the West. To circumvent that, the Trump administration tried another approach, negotiating with the Taliban first to get a deal that would lead to Taliban talks with Afghans inside and outside the government.

"It's another example of the Trump administration's foreign policy, which is a high-wire act that ultimately is focused on Trump as a persona but not in the strategic, methodical effort of creating peace," Menendez said.

Conflict continues for nearly 18 years

Cancelling the talks also goes against Trump's pledge to reduce the remaining 13,000 to 14,000 U.S. troops in Afghanistan to 8,600 and end U.S. involvement in a conflict that is closing in on 18 years.

Pompeo said he didn't know if Trump will follow through on his pledge.

Zalmay Khalilzad, the Trump administration's peace envoy in talks with Taliban leaders for months, said less than a week ago that a deal had been reached "in principle" with the group and that it only needed Trump's approval. The president, however, came under increased pressure from the Afghan government and some U.S. lawmakers who mistrust the Taliban and think it's too early to withdraw American forces.

"Unbeknownst to almost everyone, the major Taliban leaders and, separately, the President of Afghanistan, were going to secretly meet with me at Camp David on Sunday," Trump tweeted.

Trump also called off an apparent secret meeting with Afghan President Ashraf Ghani. (Matt Dunham/Associated Press)

"They were coming to the United States tonight. Unfortunately, in order to build false leverage, they admitted to an attack in Kabul that killed one of our great great soldiers, and 11 other people. I immediately cancelled the meeting and called off peace negotiations," he wrote.

On Thursday, a Taliban car bomb exploded and killed an American soldier, a Romanian service member and 10 civilians in a busy diplomatic area near the U.S. Embassy in Kabul. The bombing was one of many attacks by the Taliban in recent days. Sgt. 1st Class Elis A. Barreto Ortiz, 34, was the fourth U.S. service member killed in the past two weeks in Afghanistan.

"What kind of people would kill so many in order to seemingly strengthen their bargaining position? They didn't, they only made it worse!" Trump tweeted. "If they cannot agree to a ceasefire during these very important peace talks, and would even kill 12 innocent people, then they probably don't have the power to negotiate a meaningful agreement anyway. How many more decades are they willing to fight?"

It remains unclear if the U.S.-Taliban talks are over or only paused. Trump said he called off the peace negotiations after the bombing, though Khalilzad, the U.S. envoy negotiating with the Taliban, was meeting with leaders of the insurgent group in Doha, Qatar, on both Thursday and Friday.

Later on Sunday, Secretary Pompeo stated the Trump administration has recalled Khalilzad​, and that it is up to the insurgent group whether talks will resume.

The Afghan government, sidelined from the negotiations, seemed hesitant to directly respond to Trump's announcement, saying simply that "we have always said that a real peace will come when the Taliban stop killing Afghans and implement a ceasefire and start direct negotiations with the Afghan government" on the country's future — talks that were meant to quickly follow a U.S.-Taliban deal.

The Taliban's new statement said those talks had been meant to start on Sept. 23, five days before Afghanistan's presidential election.

Afghan presidential spokesperson Sediq Sediqqi confirmed that Afghan President Ashraf Ghani had wanted to go to Washington to speak with Trump about his concerns, "but I am not able to go into the details of the particular trip." The details of the U.S.-Taliban deal that had been shown to Ghani last week "were not convincing," Sediqqi said. "Let's see the future."