The man accused of opening fire at a Walmart in El Paso, Texas earlier this month -- killing 22 people and injuring more than 20 others -- has been placed on suicide watch, police said Monday.

The 21-year-old Dallas man was placed under close guard this week by El Paso County Jail officials after medical staff recommended he be put on watch, Spokeswoman Christina Acosta with the El Paso County Sheriff’s Office said Monday.

PARTNER OF EL PASO SHOOTING VICTIM OVERWHELMED BY HUNDREDS OF STRANGERS AT FUNERAL

She declined to go into further details about what led to that determination, citing privacy requirements. Although Fox News has identified the accused gunman, neither his name nor his photo are being aired or published unless necessary for clarity.

The suspect, who's been in police custody since the Aug. 3 shooting, was reportedly separated from other inmates in a single-person cell, although it was not immediately clear from reports what specific measures the jail was taking while he was under suicide watch, the El Paso Times reported.

Police say the suspect, who's being held without bond on capital murder charges, confessed to targeting Mexicans when he opened fire on back-to-school shoppers. An online manifesto speaking of a “Hispanic invasion of Texas” has been attributed to him by investigators.

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He was taken into custody without incident shortly after the massacre.

The Associated Press contributed to this report.