Thomas Markle Not Allowed to Return to Assisted Living Facility After Arrest

Thomas Markle Sr. was forced to find somewhere else to stay after his arrest on a federal child pornography charge ... 'cause his assisted living facility wouldn't let him back in ... TMZ has learned.

A source familiar with the case tells TMZ ... as of Friday, the Maravida Senior Living facility in Lakeland, Florida, would not allow Meghan Markle's estranged father to return following his release from custody.

We're told Thomas was instead released into the care of his daughter, who also lives in Lakeland. Our source says the U.S Marshals are monitoring Markle while he is staying at his daughter's home.

As we previously reported ... Thomas was arrested Friday by the FBI and charged with one count of possession of child pornography. The 82-year-old appeared in federal court in Tampa that afternoon and was released on bond.

Over the weekend, Samantha Markle's boyfriend, Mark Phillips, was photographed removing belongings from Thomas' residence at the senior living facility.

In the photos, Mark could be seen carrying crutches, a walker and a TV box to a vehicle ... while others hauled out trash bags.

Thomas has adamantly denied the allegations against him.

He faces up to 20 years in federal prison if convicted.