I checked out how this could be done---Djibouti(seaport) in Djibouti(Country) is linked by a RR to Addis Ababa, Ethiopia's capital. Does Ethiopia have good relations with Dijbouti? Does Ethiopia have a Navy?
I know we have special ops on the ground all over the place in the Horn of Africa, and they've been there for quite a while now. It would seem easy enough for our ops to arrange to have about 4 of those unmarked hydrofoils in Djibouti Harbor by Friday. Ad some air patrols (Ethiopia certainly does have an air force) to fill in the gaps in surface coverage, and the job's all but done.
I don't think the USA wishes to signal our involvement beyond diplomatic support---which seems a bit like disinformation, from what I reading in the news.
You can tell by my handle that I'm a nautical freak...man, would I like to have one of those 'foils!