Thomas Markle: Security Monitoring Florida Home in Senior Living Facility Amid House Arrest

Meghan Markle's estranged dad Thomas Markle Sr.'s Florida home is under surveillance by security guards at his assisted living facility ... as he remains under house arrest following his federal child pornography charge.

In the photos ... security guards from Hammerhead Security can be seen standing outside his home and walking around the outdoor premises of Maravida Senior Living in Lakeland, Florida.

One of the guards seemingly wore a camouflaged armored vest ... while the other 2 donned black shirts and pants.

We reported earlier ... Thomas Sr. was already released on bond following his Friday arrest.

As TMZ previously reported ... the FBI placed Thomas Sr. in cuffs at the senior living facility after several allegations were made against him in the U.S., the Philippines and Mexico involving the possession of child sexual abuse images.

Prosecutors claim that authorities had searched storage units that Thomas Sr. had rented that allegedly contained photos of him with nude girls.

Officials in the Philippines have called the material they've analyzed as belonging to a sex offender of the "grossest kind" ... with Mexico officials also raiding a separate storage unit that Thomas Sr. rented in Rosario.

Thomas Sr. -- who was charged with one count of possession of child pornography -- has denied the claims against him ... and said that he's never slept with anyone underage.