US looking at increased role against Iran proxies in Yemen

CNN:

The Trump Administration is expected to decide as soon as this week on a plan to increase US military involvement in Yemen's civil war.

The proposal calls for stepping up military assistance to support Saudi Arabia and the United Arab Emirates in their fight against the Iran-backed Houthi rebels who have toppled the central government there. The move would have significant implications for the US military posture on Iran, while Yemen is a key location for a top al Qaeda affiliate.

The proposal is part of the overall military plan to counter ISIS being reviewed by the White House, a US defense official said. But in contrast to other parts of the strategy, increased US support to the Saudis and UAE in Yemen could be interpreted by Iran as the beginning of a Trump administration effort to build an anti-Iranian military coalition, the official acknowledged.

The defense official noted that if Iran perceives US assistance to Tehran's foes in Yemen as an anti-Iranian move, it could hurt US efforts to fight ISIS in Syria and northern Iraq, where pro-Iranian militias have until now largely stayed away from interfering with US efforts.

The White House and Pentagon have not publicly indicated that they are trying to build an anti-Iranian coalition, although Defense Secretary James Mattis is known to be determined to curb Iran's influence.

The most immediate decision for the White House and Pentagon is whether to provide the UAE with intelligence and air refueling in their upcoming efforts to stage an amphibious assault on the Yemeni coastline to retake key areas.

Ongoing Emirati military operations inside Yemen have provided the US with intelligence about what is happening inside the country and with intelligence about the al Qaeda affiliate there, known as Al Qaeda in the Arabian Peninsula (AQAP).

The US has provided similar assistance in the past but has come under criticism in the international community due to the high level of civilian casualties the Gulf efforts in Yemen have caused.
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There is more.

I suspect that Iran sees US operations in Iraq and Syria as helpful to its allies in the Iraqi and Syrian governments.  In the long run, the Arab States fighting the Houthis in Yemen are doing strategic work to prevent Iran from controlling of an important waterway in the Red Sea.  Iran is an enemy of the US and the Gulf States and such an alliance with those fighting its proxies is a natural situation.

The reason for the high number of civilian casualties is mainly due to the way the Iranian proxies choose to fight.  They continue to concentrate their forces in civilian areas.