A suicide bomber first struck the military unit responsible for providing security for the academy, followed by a gunbattle with the troops, said Dawlat Waziri, spokesman for the Afghan defense ministry.
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At least five insurgents were involved in the early-morning assault, according to Waziri. Two of the attackers were killed in the gunbattle, two detonated their suicide vests and one was arrested by the troops, he said.
Hours later, the Islamic State group's affiliate in Afghanistan, known as Khorasan Province, posted its claim of responsibility on the website of its media arm, the Aamaq news agency, saying its fighters targeted the "military academy in Kabul."
The academy, known as Marshal Fahim National Defense University located on the edge of Kabul at the Camp Qargha military base, is sometimes also called "Sandhurst in the Sand" — a reference to the British academy. Named after Mohammed Fahim, the country's late vice-president and a military commander of the Northern Alliance that fought the Taliban, the academy was inaugurated in 2013 after British forces oversaw building the officers' school and its training program.
The academy was also the site where the highest-ranking U.S. military officer to be lost in the Afghan and Iraqi wars was killed in August 2014. Army Maj Gen. Harold J. Greene, then deputy commander of the transition force in the country, was shot and killed by an Afghan soldiers in a so-called "insider attack" that was later claimed by the Taliban.
The same academy was also attacked in October last year by a suicide bomber who killed 15 officers. The attacker was on foot and detonated his suicide vest as the on-duty officers were leaving the facility, heading home in the evening. That attack was also claimed by the Taliban.
Both the Taliban and IS have stepped up attacks in recent months in Kabul and elsewhere across Afghanistan, including massive bombings staged by militants determined to inflict maximum casualties, instill terror in the population and undermine confidence in Afghan President Ashraf Ghani's government and the country's security forces.
On Saturday, a Taliban attacker drove an ambulance filled with explosives into the heart of the city, killing at least 103 people and wounding as many as 235.
The recent brutal attacks have underscored the weaknesses of Afghan security forces, more than 16 years after the U.S.-led invasion toppled the Taliban, and raise questions about President Donald Trump's strategy for winning America's longest war.