KABUL -- A suicide bombing targeting a military academy in a southern neighborhood of Kabul has killed at least five people, in what was described as the first major assault in the Afghan capital in months.
The attack came as Afghan President Ashraf Ghani wrote on Twitter that he had been informed by U.S. Secretary of State Mike Pompeo of "notable progress" in peace talks with the Taliban, which has denied involvement in the bombing.
The Defense Ministry told RFE/RL that the February 11 blast at a checkpoint near the entrance of the government-run Marshal Fahim Military Academy claimed five lives.
However, Interior Ministry spokesman Nasrat Rahimi put the death toll at six, saying those killed included four army personnel and two civilians.
Rahimi said 12 people were wounded, including five civilians.
No group immediately claimed responsibility for the attack, which happened around 7 a.m. local time as employees and cadets were entering the academy.
The Taliban militant group denied any involvement in the attack in a statement to news agencies through a WhatsApp message.
A security source was quoted as saying the attacker was on foot when he targeted a vehicle as it was entering the facility.
A witness said there was a big explosion followed by gunfire.
The academy has been the scene of several attacks in the past, including an assault in May last year that was claimed by the Islamic State (IS) extremist group.
The latest attack comes as U.S. and Taliban negotiators wrangle over a possible peace deal to end the nearly two-decade war.
Afghan President Ashraf Ghani called the bombing "a crime against humanity" and reiterated his call for a nationwide cease-fire.
He later wrote on Twitter that he had received a call from Pompeo, who told him of "notable progress" in the ongoing peace talks between U.S. and Taliban negotiators.
"The Secretary informed me about the Taliban’s proposal with regards to bringing a significant and enduring reduction in violence," Ghani wrote without providing specifics.
Pompeo last week demanded "demonstrable evidence" from the Taliban that it will lower the violence level in Afghanistan before signing a deal that would lead to peace talks and a withdrawal of American troops from the country.
However, the extremist group rejected Pompeo's demands and accused the United States of impairing negotiations, and it remains unclear where talks now stand following conflicting comments from those involved.
In Brussels, NATO Secretary-General Jens Stoltenberg said the Kabul attack "shows the consequences of horrendous violence against innocent civilians" and "demonstrates the strong need to find a peaceful resolution" to the Afghan conflict.
"We are troubled by this attack," the U.S. envoy to NATO, Kay Bailey Hutchison told RFE/RL in Brussels.
"We are hoping that we can have a peace accord that will take the process to an intra-Afghan dialogue that will allow all of the Afghan community groups, citizens' groups, to sit at the table and determine for themselves what they want for the country," she added.
On February 10, President Donald Trump traveled to Dover Air Force Base in Delaware to pay respects to two U.S. soldiers killed this weekend in Afghanistan.
The two U.S. servicemen were killed and six others were wounded in Afghanistan's eastern Nangarhar Province on February 8 when a soldier dressed in an Afghan National Army uniform opened fire with a machine gun.
A total of six U.S. service members have been killed in Afghanistan since the start of the year.