STORY: Here are five business stories making headlines in sub-Saharan Africa this week.

Nigeria's central bank surprised analysts and traders on Tuesday (May 24) by raising the benchmark interest rate 150 basis points to 13%.

The hike, Nigeria's first in two years, is intended to combat rising inflation, but also sent markets tumbling.

The United States issued an advisory on Monday (May 23) warning American companies of the growing "reputational risks" of doing business with state-owned enterprises and military-controlled firms in Sudan.

The country has witnessed regular protests since a military coup in October, and lawyers say dozens of political prisoners remain in detention.

Somalia's prime minister has suspended his foreign minister, citing the authorization of a ship exporting charcoal to Oman - in violation of international sanctions.

The U.N. Security Council banned such shipments a decade ago to cut funding for the militant group al Shabaab.

Russian aluminium giant Rusal has called a strike at its Guinea subsidiary's bauxite mine "illegal".

Workers at the COBAD facility have downed tools, a union leader said on Thursday (May 26), demanding better working conditions and a salary increase.

And finally, Central African Republic is to launch Africa's first legal cryptocurrency investment hub, the presidency has said.

It's an extension of the impoverished country's embrace of digital finance, despite words of caution from the International Monetary Fund.

Marred by decades of conflict, CAR last month became the first country in Africa and only the second in the world to adopt bitcoin as an official currency.