The US has blacklisted several individuals in Somalia accused of giving the Islamist al-Shabab group financial and other material assistance.
Washington says they are part of a network that has engaged in smuggling weapons from local and foreign sources.
This comes a day after the Somali authorities warned businesses in the capital, Mogadishu, against paying taxes to the al-Qaeda affiliate.
Al-Shabab frequently extorts businesses in Mogadishu raising tens of millions of dollars for their militant activities in Somalia and neighbouring countries.
President Hassan Sheikh Mohamud has declared an all-out war against al Shabab and sought international support to defeat the militants.