The Treasury Department said Monday that it has sanctioned a group of high-ranking members of the Somalia-based al-Shabab militant group, who act as key middle men between the group and local companies in Somalia.

Treasury’s Office of Foreign Assets Control imposed the sanctions on more than a dozen individuals from Somalia and Yemen who are involved in al-Shabab’s financing operations which in turn use those funds to assist in weapons procurement and recruitment activities.

One member is accused of using digital currency to launder money for the group.

Along with the Treasury sanctions, the State Department on Monday designated five al-Shabab leaders for diplomatic penalties.

“Treasury is focused on identifying and disrupting al-Shabab’s illicit networks operating in Eastern Africa,” said Brian E. Nelson, Treasury Under Secretary for Terrorism and Financial Intelligence.

“We will continue to take action against the weapons smuggling and fundraising activities of al-Shabab and other al-Qaida affiliates.”

Al-Shabab officially became an affiliate of al-Qaida, the Islamist association founded by Osama bin Laden, in 2012. The group maintains strong connections to al-Qaida’s senior leaders has financed al-Qaida’s efforts worldwide.

The U.S. says Al-Shabab generates around $100 million per year through extorting local businesses and individuals, collecting fees on goods, and facilitating illicit trades.