The Yemeni government (along with the Saudis, Egyptians, Jordanians and Moroccans) are trying to fight back the Iranian-supported Houthi rebels, some of whom are being trained by the Revolutionary Guards in Eritrea.
This is a full-blown proxy war.
Now, at the same time, the already-stretched-thin Yemeni government is expected to fight Al-Qaeda, which it has tried to strike deals and truces with just like Pakistan has tried to do.
The Yemeni security forces has high-level sympathizers of Salafi extremism, and so the comparison is pretty solid.
If the U.S. wants Yemen to stop tolerating Al-Qaeda and other radical Sunni elements as a way of fighting the Shiite Houthis, then the U.S. will need to threaten the Yemenis as well as offer to be a far better partner than those militants ever could be.