WASHINGTON (NYTIMES) - For years, the US military has sought to distance itself from a brutal civil war in Yemen, where Saudi-led forces are battling rebels who pose no direct threat to the United States.
But late last year, a team of about a dozen Green Berets arrived on Saudi Arabia's border with Yemen, in a continuing escalation of America's secret wars.
With virtually no public discussion or debate, the army commandos are helping locate and destroy caches of ballistic missiles and launch sites that Houthi rebels in Yemen are using to attack Riyadh and other Saudi cities.
Details of the Green Beret operation, which has not been previously disclosed, were provided to The New York Times by US officials and European diplomats.
They appear to contradict Pentagon statements that US military assistance to the Saudi-led campaign in Yemen is limited to aircraft refuelling, logistics and general intelligence sharing.
There is no indication that the US commandos have crossed into Yemen as part of the secretive mission.
But sending US ground forces to the border is a marked escalation of Western assistance to target Houthi fighters who are deep in Yemen.
Beyond its years as a base for Al-Qaeda in the Arabian Peninsula, Yemen has been convulsed by civil strife since 2014, when Shi'ite Muslim rebels from the country's north stormed the capital, Sanaa.
The Houthis, who are aligned with Iran, ousted the government of President Abed Rabbo Mansour Hadi, the Americans' main counter-terrorism partner in Yemen.
In 2015, a military coalition led by Saudi Arabia began bombing the Houthis, who have responded by firing missiles into the kingdom.
Yet there is no evidence that the Houthis directly threaten the United States; they are an unsophisticated militant group with no operations outside Yemen and have not been classified by the US government as a terrorist group.
The Green Berets, the army's Special Forces, deployed to the border in December, weeks after a ballistic missile fired from Yemen sailed close to Riyadh, the Saudi capital.
The Saudi military intercepted the missile over the city's international airport, and Crown Prince Mohammed bin Salman renewed a long-standing request that the United States send troops to help the kingdom combat the Houthi threat.