The United States on Tuesday put on its terror blacklist the leader of an elite unit of Al-Shabaab blamed for a January attack in Kenya that killed three Americans.
The State Department said that it was listing Maalim Ayman, leader of the Al-Shabaab squad Jaysh Ayman, as well as Abdullahi Osman Mohamed, who manages both explosives and media for the Al-Qaeda-linked movement as a whole, as Specially Designated Global Terrorists.
Authorities say the Jaysh Ayman unit carried out the January attack on Camp Simba on Kenya's northern coast, killing three American personnel and destroying several aircraft.
A 2018 study by the Jamestown Foundation described Jaysh Ayman as the Somali-based Al-Shabaab's effort to create a well-equipped "local" unit inside Kenya.
Kenya has suffered a series of devastating attacks since it sent troops into Somalia in 2011 as part of an African Union mission that chased Al-Shabaab out of the capital Mogadishu.
Al-Shabaab -- designated by Washington as a terrorist movement in 2008 -- was suspected in another suicide attack Tuesday at a Mogadishu restaurant that killed at last five people.
Nathan Sales, the State Department counterterrorism coordinator, said that the United States was working with Kenya, Somalia and other nations to apply "all instruments of national power" against Al-Shabaab.
The designation freezes any assets the individuals may have in the United States and makes it a crime to assist them.
"Whether or not they have assets in the United States, sanctions have very powerful secondary consequences because it makes it that much harder for designated individuals or organizations to move money in the international financial system," Sales told reporters.