Chris Brown is in jail and is being held without bail. in L.A.  The arrest was made at 2 p.m. PT on a warrant relating to a probation violation in his 2009 conviction for assaulting Rihanna.

According to TMZ, he was kicked out of the rehab center in Malibu where he has been undergoing court-ordered treatment as part of his probation in that case, and that this led to the arrest.

Chris was ejected Friday morning for violating "internal rules," but they won't say which rules he violated.  It is clear that it did not involve drugs or violence, and another source added that, while the singer was caught having "an inappropriate relationship" with a female employee earlier in the month, it wasn't that infraction that resulted in him being ejected.

Brown had been in the rehab center for four months.  Although he had completed an initially-mandated 90 days in the center, earlier this month he was ordered by a judge to remain there for an additional two months while his Washington, D.C assault case is pending.  That case is slated to go to trial next month.

He was previously dismissed from a different facility for throwing a rock at a window in his mother's car.

Keep Chris Brown in your prayers.