The ‘Hellfire Ninja R9X’ missile attacks by launching pop-out swords to take down its victims, rather than an explosive.
The weapon has six extendable blades which attack the target on impact, and importantly, does not trigger a blast which reduces the risk of massive collateral damage of nearby civiilans and infrastructure.
The Al-Qaeda leader was hit by the strike when he stepped onto the balcony of his safe house in the Shirpur neighbourhood of Kabul.
Mr Biden said the attack showed, “That no matter how long it takes, no matter where you hide. If you are a threat to our people, the United States will find you and take you out”.
Al-Zawahiri was 71-years-old.
The missile was developed under former president Barack Obama after concerns over the number of civilan deaths resulting from air strikes.
However, in a 2019 report in the Wall Street Journal – who said the R9X was referred to as the “flying Ginsu” after popular brand of steak knives- there were concerns expressed over the use of the missile.
Human Rights Watch’s Letta Tayler wrote: “On its own, the R9X won’t resolve the host of legal issues surrounding the US targeted killing programme, which since 2002 has killed thousands of people with scant transparency.”
The strike happened just under a year after the US withdrew its military, and evacuated tens of thousands of people as the Taliban retook the country.
The Taliban, apparently once again host to the Al-Qaeda leader, confirmed the airstrike, but did not mention al-Zawahri or any other casualties.
It said it “strongly condemns this attack and calls it a clear violation of international principles and the Doha Agreement,” the 2020 US pact with the Taliban that led to the withdrawal of American forces.
In a statement, the Taliban added: “Such actions are a repetition of the failed experiences of the past 20 years and are against the interests of the United States of America, Afghanistan, and the region.”