US President Barack Obama speaks at Marine Corps Base-Camp Pendleton in California, August 7, 2013. [Photo/Agencies]

CAMP PENDLETON, Calif - US President Barack Obama used a stop at a military base in California on Wednesday to speak out against sexual assault within the US armed services.

Finishing a two-day trip to Arizona and California during which he promoted new housing reform proposals, Obama came to Camp Pendleton to thank military members for their service and warn Americans that al-Qaida was still a threat.

But his comments about sexual assault to roughly 3,000 Marines and Navy members highlighted another problem that has dogged in the military: high levels of sexual assault among the armed forces.

The Pentagon reported in May that there had been a 37 percent jump in cases of unwanted sexual contact in the military from 2011 to 2012, from gropings to rape. Sixty people have been removed from jobs as military recruiters, drill instructors and victims counselors as a result of screenings order following the report.

"I want you to hear it directly from me, the commander-in-chief," Obama said. "It undermines what this military stands for and it undermines what the Marine Corps stands for when sexual assault takes place within."  

Debate over the military's sexual assault problem has been intense since a spate of high-profile cases.

Obama said it is critical to "stop these crimes of sexual assault and uphold the honor and the integrity that defines the finest military on earth".