The Russian buildup in Syria has produced a lot of media attention and expressions of concern, but Syria isn't the only war attracting foreign military intervention. Within days of the death in Yemen of 45 UAE troops (along with 10 Saudi and five Bahraini troops), Qatar announced that it was deploying 1,000 ground troops to Yemen to join the Saudi-led coalition there, its first dispatch of ground troops there, and Bahrain's King Hamad announced that two of his sons would go to Yemen as part of their national service.
All of the GCC states except for Oman are now participating in the Yemen coalition, and with the Qatari deployment all will have ground troops in Yemen except Kuwait, which is contributing aircraft. Egypt, Jordan, and Sudan are also participating militarily in various ways, and now there are reports that Moroccan ground troops will also be joining the coalition. Reports suggest that up to 6,000 Sudanese troops may be coming as well.
At a time when it is still not clear whether the Russian buildup in Syria is intended to participate in combat or is merely there for force protection and regime protection, it is interesting that there is much less attention (at least in the US media) to the growing ground force commitment in Yemen.