In a series of tweets Saturday night, President Trump wrote that he called off a secret meeting at Camp David with the Taliban and canceled. The president wrote that the Taliban "admitted" to an attack in Kabul that "killed one of our great great soldiers" and 11 others.
U.S. Secretary of State Mike Pompeo said on Friday that the Trump administration has "made a lot of progress in convincing the Taliban to make some commitments that, frankly, we've been trying to get out of them for almost two decades now."
CBS News reported on Friday that Afghan President Ashraf Ghani had postponed a trip to the U.S. but it had yet to be rescheduled.
"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. They were coming to the United States tonight," Mr. Trump wrote in the first tweet.
Mr. Trump then wrote that "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."
A car bomb attack in Kabul on Thursday killed Sgt. 1st Class Elis A. Barreto Ortiz, 34, from Puerto Rico. A Romanian service member was also killed in the attack, as were at least 10 Afghan citizens. It was the second Taliban attack in Kabul in less than a week. The Taliban launched military offenses in three provinces last week.
The Taliban claimed the spike in attacks is justified to give them a stronger position in negotiations, CBS News' Charlie D'Agata reported on Friday.
"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?" Mr. Trump continued.
Mr. Trump then wrote the Taliban "only" made their bargaining position "worse."
"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?" Mr. Trump concluded.
There have been at least 16 U.S. service members killed in Afghanistan this year, according to the Defense Department.
The U.S. hopes its deal with the Taliban will bring the militant group to the table for intra-Afghan talks to begin ahead of Afghanistan's presidential election on September 28 — a vote that Ghani insisted must be held on time and not be swept aside by any kind of interim government.
Few details have emerged from the nine rounds of U.S.-Taliban talks over nearly a year. Zalmay Khalilzad, who is Mr. Trump's Afghanistan envoy, said the first 5,000 U.S. troops would withdraw from five bases in Afghanistan within 135 days of a final deal. Between 14,000 and 13,000 troops are currently in the country.
However, the Taliban want all of the approximately 20,000 U.S. and NATO troops out of Afghanistan as soon as possible.
For its part, the U.S. seeks a guarantee from the Taliban that they will not allow Afghanistan to become a haven from which extremist groups like al-Qaeda and ISIS can launch global attacks.