BALTIMORE -- The Maryland Stadium Authority has increased security around the Ray Lewis statue outside M&T Bank Stadium after the former All-Pro linebacker joined Ravens players in kneeling during the national anthem, which spurred an on-line petition to remove the 3-year-old landmark.

The petition on change.org has received more than 50,000 signatures as of Thursday morning.

The extra security has been in place since Sunday afternoon, a spokeswoman for the Maryland Stadium Authority told The Baltimore Sun. A Ravens spokesman declined comment to ESPN.

Ray Lewis joined 13 Ravens players in kneeling during the anthem prior to Sunday's game against Jacksonville. He later said he was praying. AP Photo/Matt Dunham

Last Sunday, Lewis joined 13 Ravens players in kneeling during the anthem before Baltimore's 44-7 loss to the Jacksonville Jaguars in London. The Ravens players said they were protesting President Trump's recent comments that NFL owners should fire players who didn't stand during the anthem.

Lewis later said he was praying.

"I dropped on two knees -- both knees -- so I can simply honor God in the midst of chaos," Lewis said on Showtime's "Inside the NFL."

President Trump, in an interview that aired Thursday on "Fox and Friends," continued to call for NFL owners to take action against those who kneel during the national anthem to protest racial injustice.