Two veteran Los Angeles Police Department officers who worked as partners assigned to the Hollywood Division have been charged with repeatedly sexually assaulting four women, often while the pair was on duty, prosecutors said.

James Nichols, 44 and Luis Valenzuela, 43, are scheduled to be arraigned on Thursday in connection with the case, according to the Los Angeles County District Attorney's office. Prosecutors will ask that bail be set at $3.83 million for Nichols and $3.76 million for Valenzuela, a statement said.

Beginning in December 2008, after they became partners, and continuing through March 2011, the two men allegedly began sexually assaulting women at various locations, including in their police vehicle, prosecutors said. All four women were arrested at various times by the officers during narcotics-related offenses, prosecutors said.

At the time the alleged assaults occurred, the victims were 19, 24, 25 and 34 years of age, according to prosecutors. Most, but not all, of the alleged sexual assaults occurred while the officers were on duty.

Nichols and Valenzuela are charged with multiple counts each of sexual assaults, including forcible rape, rape under color of authority, oral copulation under color of authority and oral copulation by force.

In a lawsuit settled with one of the victims, the woman alleged in 2009 that she was assaulted in the back of the pair's police vehicle.

She also alleged that the officers told her to "stay quiet" and they would get her a marijuana card. The suit says that they offered to buy her a ticket to Las Vegas if she would promise to "go there and never come back."

In another incident alleged in the settlement, the victim said Valenzuela asked her to go to a motel room with him and smoke methamphetamine. She said he wanted to "watch her" smoke it.

Valenzuela is also charged with one count of assault with a firearm for allegedly pointing a gun at one of the victims.

During an afternoon news conference, LAPD Chief Charlie Beck called the officers a disgrace to the department and to the badge. He said the officers are still with the department, but have been relieved of duty without pay since 2013.

Craig Lally, the president of the Los Angeles Police Protective League, the union that represents rank-and-file officers, said in a statement that the arrests are "deeply disturbing."

"We hope the allegations are not true," he said. "While the arrests are troubling, it is important to allow the court process to fully run its course."

The Los Angeles Police Department's Robbery-Homicide Division, which often investigates high-profile crimes, presented the case to the district attorney's office.

If convicted, Nichols and Valenzuela each face up to life in state prison.