File Photo: U.S. soldiers participate in Exercise Eager Lion at the Jordan-Saudi Arabia border, south of Amman May 18, 2015. (Xinhua/REUTERS)

WASHINGTON, Nov. 1 (Xinhua) -- The United States Central Command on Thursday apologized for including discriminatory language in a welcome guide offered to troops deployed in Saudi Arabia.

The June 2018 guide, designed to inform newly deployed troops about the kingdom's culture and customs, said in one paragraph a "mixture of negro blood from slaves imported from Africa" can be found in some of the kingdom's population.

Bill Urban, a spokesman of the command, said in a statement that "we regret that inappropriate material was posted to our website without a more fulsome review and apologize to anyone who took offense."

"We removed the document as soon as we were notified of the content, and it was returned to the originating office for revision," Urban said.

The Central Command will review other training material for inappropriate content, he said.

The offensive wording was brought to light by comedian Hasan Minhaj, who joked on his show that "Oh America, even in boring, technical manuals you somehow manage to be racist."

It is unclear how the language was inserted into the guide in the first place, U.S. media said the tone of the language was dated from several decades ago, suggesting that the wording might have been pulled from an older material.

The U.S. Central Command is a theater-level Unified Combatant Command headquartered in the U.S. state of Florida. Its Area of Responsibility includes countries in West Asia, parts of North Africa, and Central Asia, most notably Afghanistan and Iraq.