President Donald Trump said on Saturday, Sept. 7, that he had called off a secret weekend meeting at Camp David with Taliban and Afghanistan leaders after a bombing this week in Kabul killed 11 people, including an American soldier, and has dropped peace negotiations with the insurgent group.

Zalmay Khalilzad, the special representative for Afghanistan Reconciliation at the State Department, talked with Taliban officials in the last couple of months and said he was on the threshold of a deal with the Taliban to end the longest conflict in America.

“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 Saturday evening.

“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 canceled the meeting and called off peace negotiations,” he added.

On Thursday, a 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. This bombing was one of the many Taliban attacks in recent days during the U.S.-Taliban talks.

According to the Defense Department, Sgt. 1st Class Elis A. Barreto Ortiz, 34, from Morovis, Puerto Rico, was killed in action when the explosive device detonated near his vehicle, being the fourth U.S. service member killed in Afghanistan over the past two weeks.

“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 cease-fire 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’s unclear whether the talks between the United States and the Taliban are over or paused.

Khalilzad, suddenly returned to Qatar late last week for unexpected talks with the Taliban about the deal he had described as complete just days earlier. Khalilzad said last Monday that only Trump’s approval was needed for the “in principle” agreement to start a U.S. troop withdrawal.

The Taliban clarified its rise in lethal assaults, which included the capitals of the southern provinces of Kunduz and Baghlan last weekend, as needed to offer them a stronger bargaining position in discussions with the United States.

On Friday, Khalilzad convened with Taliban lead negotiator Mullah Abdul Ghani Baradar and U.S. forces chief in Afghanistan, Gen. Scott Miller, with Qatar’s overseas minister present, Taliban spokesman Suhail Shaheen said late in the afternoon in a tweet. “Positive” were both Thursday’s and Friday’s conferences, he said.

Includes reporting from the Associated Press