“They have done it again. The U.S., Britain and regional allies led by Saudi Arabia have come together to intervene in another country with calamitous results,” writes renowned Middle East reporter Patrick Cockburn in a recent article.

“They have produced chaos, ruining the lives of millions of people and creating ideal conditions for salafi-jihadi movements like al-Qaeda and Islamic State.”

Cockburn is speaking of the war in Yemen, a conflict that is little-discussed in the U.S., but has tremendous importance in the Middle East.

Since March 2015, Saudi Arabia has waged a brutal war on Yemen, the poorest country in the Middle East.

In the name of fighting Yemen’s Houthi fighters and rebels loyal to former President Ali Abdullah Saleh, a coalition led by Saudi and armed and supported by the U.S. and U.K. has bombed numerous Yemeni cities, shelling civilian areas including neighborhoods, hospitals, schools, weddings, an Oxfam humanitarian aid warehouse and even a refugee camp.

Cockburn joins a growing list of analysts and experts who argue that the party that has gained the most from the war in Yemen has not been Saudi Arabia and its Western allies, but rather extremist groups like al-Qaeda.

“The real winners in this war are al-Qaeda in the Arabian Peninsula (AQAP) which has taken advantage of the collapse of central government to create its own mini-state,” he writes.

AQAP has long been one of the most violent and feared branch of the extremist group. It has ruthlessly killed opponents, and even sometimes crucifies those whom it kills, hanging them from bridges.

Ansar al-Sharia, a local wing of AQAP in Yemen, flies the ISIS flag. Some members of the extremist group have left and joined ISIS.

Now, Cockburn explains, AQAP controls a 340-mile area on the south coast of Yemen, where it has created its own government of sorts with tax revenues.

Just as the war has received little coverage in U.S. media outlets, its catastrophic consequences have been even less acknowledged.

“Unnoticed by the outside world, AQAP has been swiftly expanding its own statelet in Yemen in 2015/16, just as ISIS did in western Iraq and eastern in Syria in 2013/14,” he continues.

“The dire consequences of the Saudi intervention and the rise of AQAP has been largely ignored by Western governments and media,” Cockburn explains in the article, published Friday in the British newspaper The Independent.

“Contrary to their grim-faced declarations about combating terrorism, the U.S. and U.K. have opened the door to an al-Qaeda mini-state.”

In the article, titled “Thanks to U.K. and U.S. intervention, al-Qaeda now has a mini-state in Yemen. It’s Iraq and ISIS all over again,” Cockburn criticizes the U.S. for underestimating the threat of ISIS in Iraq and Syria, just as Washington and London underestimated the threat of AQAP in Yemen.

He also notes how the war has inflamed sectarian tensions in the country.

Yemen has large Shia and Sunni Muslim populations, “but it is only recently that sectarian hatred has begun to get anywhere near the level of Syria and Iraq,” he explains.

“Saudi Arabia portrays the Houthis as pawns of Iran, though there is little evidence for this, so Yemen is drawn into the regional confrontation between Saudi Arabia and Iran.”

Investigative journalist Gareth Porter has debunked claims that the Houthis are armed by Iran, although Western media outlets frequently misreport this.