A member of the Afghan security forces stands guard at the site of a blast in Kabul on Thursday. (Mohammad Ismail/Reuters)

A suicide bomber detonated a vehicle filled with explosives Thursday afternoon outside the national military academy here, killing at least six people and wounding 16, officials said.

The vehicle exploded as cadets at the Marshal Fahim National Defense University were leaving the hillside campus overlooking the Afghan capital for their weekly two-day break. The extremist Islamic State group asserted responsibility for the bombing.

The attack occurred after three days of Afghan peace talks in Moscow concluded without any significant progress in ending the war, or even the hoped-for announcement of a cease-fire at the end of the holy month of Ramadan next week. Last June, a three-day truce raised nationwide hopes for a war settlement.

In the talks, a 14-member Taliban delegation headed by Abdul Ghani Baradar held several lengthy closed-door meetings with Afghan power brokers. They did not include representatives of the elected Kabul government, which the insurgents view as a U.S. puppet, although members of a government-appointed peace council attended the conference. 

The participants included former president Hamid Karzai, former national security adviser Hanif Atmar — a key contender challenging President Ashraf Ghani in elections slated for September — and Atta Mohammad Noor, a former provincial governor and influential figure. 

Noor publicly appealed to the Taliban on Tuesday, when the conference opened, to propose a cease-fire before the talks ended. But a Taliban spokesman said Thursday no truce would be offered, although progress had been made.

The Taliban’s chief negotiator, Mohammad Abbas Stanikzai, right, and head of its political office, Abdul Ghani Baradar, left, attend peace talks with senior Afghan politicians in Moscow on Thursday. (Evgenia Novozhenina/Reuters)

“We discussed the cease-fire, and we will continue this discussion,” the spokesman, Muhammad Sohail Shaheen, told journalists. “We are satisfied with how negotiations went.” The conference marked the second such event hosted by Moscow, which brought together Taliban and influential Afghan figures in February.  

A brief closing joint statement in Pashto said both sides had discussed a range of issues, including the pullout of foreign troops, the “consolidation of the Islamic system” and women’s rights. It said that agreement was reached on some issues but that others “needed further debate.”

Baradar, a co-founder of the Taliban and head of its political office, spoke publicly for the first time Tuesday about the importance of reaching a peace deal. He indicated that months of efforts to end the 18-year war may be advancing despite continued attacks by the insurgents and the lack of progress in months of parallel U.S.-Taliban talks. 

“The Islamic Emirate is firmly committed to peace, but the first step is to remove obstacles and end the occupation of Afghanistan,” he said, using the Taliban’s formal name. 

The busiest figure at the conference, though, was Karzai, who was widely seen as the chief broker between the two sides. There were numerous group photo-ops, with Karzai in the center, flanked by Taliban representatives and Afghan politicians. 

“It was very, very positive. We had good discussions,” Karzai said as the meeting ended. “We are leaving very, very happy.”

Both the Islamic State and the Taliban have attacked the military academy since it opened in 2014 soon after the death of Muhammad Marshal Fahim, a former vice president and anti-Taliban militia leader.

In August of that year, an apparent insider attack claimed by the Taliban killed U.S. Army Maj. Gen. Harold J. Greene, the highest-ranking U.S. officer to die in the Afghanistan and Iraq wars. He was shot by a man in military uniform during a visit by U.S. and NATO generals to the facility.

In January 2018, Islamic State militants attacked Afghan soldiers guarding the academy in an early morning assault, killing 11 troops and wounding 16. Officials said a suicide bomber struck the security unit, then other militants opened fire.

In October, a suicide bomber on foot approached the walled campus as Afghan officers were leaving and detonated his vest, killing 15. The Taliban asserted responsibility for that attack.

Ferris-Rotman reported from Moscow. Sayed Salahuddin in Kabul contributed to this report.